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1. Fluorescence from a single-molecule probe directly attached to a plasmonic STM tip

Author

Niklas Friedrich, Anna Rosławska, Xabier Arrieta, Katharina Kaiser, Michelangelo Romeo, Eric Le Moal, Fabrice Scheurer, Javier Aizpurua, Andrei G. Borisov, Tomáš Neuman, and Guillaume Schull

Subjects
Science
Abstract

Abstract The scanning tunneling microscope (STM) provides access to atomic-scale properties of a conductive sample. While single-molecule tip functionalization has become a standard procedure, fluorescent molecular probes remained absent from the available tool set. Here, the plasmonic tip of an STM is functionalized with a single fluorescent molecule and is scanned on a plasmonic substrate. The tunneling current flowing through the tip-molecule-substrate junction generates a narrow-line emission of light corresponding to the fluorescence of the negatively charged molecule suspended at the apex of the tip, i.e., the emission of the excited molecular anion. The fluorescence of this molecular probe is recorded for tip-substrate nanocavities featuring different plasmonic resonances, for different tip-substrate distances and applied bias voltages, and on different substrates. We demonstrate that the width of the emission peak can be used as a probe of the exciton-plasmon coupling strength and that the energy of the emitted photons is governed by the molecule interactions with its environment. Additionally, we theoretically elucidate why the direct contact of the suspended molecule with the metallic tip does not totally quench the radiative emission of the molecule.

Published
2024
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2. Internal Stark effect of single-molecule fluorescence

Author

Kirill Vasilev, Benjamin Doppagne, Tomáš Neuman, Anna Rosławska, Hervé Bulou, Alex Boeglin, Fabrice Scheurer, and Guillaume Schull

Subjects
Science
Abstract

The internal Stark effect, a shift of the spectral lines of a chromophore induced by electrostatic fields in its close environment, plays an important role in nature. Here the authors observe a Stark shift in the fluorescence spectrum of a phthalocyanine molecule upon charge modifications within the molecule itself, achieved by sequential removal of the central protons with a STM tip.

Published
2022
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3. The influence of obesity and gender on outcome after reversed L-shaped osteotomy for hallux valgus

Author

Stephan H. Wirth, Niklas Renner, Richard Niehaus, Jan Farei-Campagna, Marcel Deggeller, Fabrice Scheurer, Katie Palmer, and Thorsten Jentzsch

Subjects
Hallux valgus deformity (HV), Reversed L-shaped osteotomy (ReveL), Long plantar arm osteotomy, Body mass index (BMI), Gender, Radiological relapse, Diseases of the musculoskeletal system, RC925-935
Abstract

Abstract Background Hallux valgus deformity (HV) affects around every fourth individual, and surgical treatment is performed in every thousandth person. There is an ongoing quest for the best surgical management and reduction of undesirable outcomes. The aim was to explore associations of obesity and gender with radiological and clinical outcome after reversed L-shaped osteotomy (ReveL) for HV. Materials and methods This study was carried out in a retrospective cohort design at a single University Hospital in Switzerland between January 2004 and December 2013. It included adult patients treated with ReveL for HV. The primary exposure was body mass index (BMI) at the time of ReveL. The secondary exposure was gender. The primary outcome was radiological relapse of HV (HV angle [HVA] > 15 degrees [°]) at the last follow-up. Secondary outcomes were improvable patient satisfaction, complication, redo surgery, and optional hardware removal. Logistic regression analysis adjusted for confounders. Results The median weight, height, and BMI were 66.0 (interquartile range [IQR] 57.0–76.0) kilograms (kg), 1.65 (IQR 1.60–1.71) metres (m), and 24.0 (IQR 21.3–27.8) kg/m2. Logistic regression analysis did not show associations of relapse with BMI, independent of age, gender, additional technique, and preoperative HVA (adjusted odds ratio [ORadjusted] = 1.10 [95% (%) confidence interval (CI) = 0.70–1.45], p = 0.675). Relapse was 91% more likely in males (ORadjusted = 1.91 [95% CI = 1.19–3.06], p = 0.007). Improvable satisfaction was 79% more likely in males (ORadjusted = 1.79 [CI = 1.04–3.06], p = 0.035). Hardware removal was 47% less likely in males (ORadjusted = 0.53 [95% CI 0.30–0.94], p = 0.029). Conclusions In this study, obesity was not associated with unsatisfactory outcomes after ReveL for HV. This challenges the previous recommendation that preoperative weight loss may be necessary for a successful surgical treatment outcome. Males may be informed about potentially higher associations with unfavourable outcomes. Due to the risk of selection bias and lack of causality, findings may need to be confirmed with clinical trials.

Published
2019
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4. Mapping Lamb, Stark, and Purcell Effects at a Chromophore-Picocavity Junction with Hyper-Resolved Fluorescence Microscopy

Author

Anna Rosławska, Tomáš Neuman, Benjamin Doppagne, Andrei G. Borisov, Michelangelo Romeo, Fabrice Scheurer, Javier Aizpurua, and Guillaume Schull

Subjects
Physics, QC1-999
Abstract

The interactions of the excited states of a single chromophore with static and dynamic electric fields spatially varying at the atomic scale are investigated in a joint experimental and theoretical effort. In this configuration, the spatial extension of the fields confined at the apex of a scanning tunneling microscope tip is smaller than that of the molecular exciton, a property used to generate fluorescence maps of the chromophore with intramolecular resolution. Theoretical simulations of the electrostatic and electrodynamic interactions occurring at the picocavity junction formed by the chromophore, the tip, and the substrate reveal the key role played by subtle variations of Purcell, Lamb, and Stark effects. They also demonstrate that hyper-resolved fluorescence maps of the line shift and linewidth of the excitonic emission can be understood as images of the static charge redistribution upon electronic excitation of the molecule and as the distribution of the dynamical charge oscillation associated with the molecular exciton, respectively.

Published
2022
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5. The influence of the number of screws and additional surgical procedures on outcome in hallux valgus treatment

Author

Thorsten Jentzsch, Niklas Renner, Richard Niehaus, Jan Farei-Campagna, Marcel Deggeller, Fabrice Scheurer, Katie Palmer, and Stephan H. Wirth

Subjects
Hallux valgus (HV), Reversed L-shaped osteotomy (ReveL), Long plantar arm osteotomy, Screws, Recurrence, Patient satisfaction, Orthopedic surgery, RD701-811, Diseases of the musculoskeletal system, RC925-935
Abstract

Abstract Background Surgical treatment of hallux valgus (HV) is one of the major flagships of orthopedic surgeons. Due to relatively unsatisfactory radiological and clinical outcomes, the search for the best surgical technique and causes for unsatisfactory outcomes continues. The objective was to investigate associations of the number of screws and additional surgical techniques for HV with radiological and clinical outcome after reversed L-shaped osteotomy (ReveL). Methods A retrospective cohort study of adults from a single University Hospital between 2004 and 2013 was performed. The primary exposure was the number of screws (one vs two) used for osseous fixation after ReveL. The secondary exposure was an additional surgical technique for HV (e.g., Akin osteotomy). The primary outcome was a radiological recurrence of HV (HV angle (HVA) > 15°) at last follow-up. The secondary outcomes were limited patient satisfaction, complication, revision surgery, and elective hardware removal. Odds ratio (OR) and 95% confidence interval (CI) were estimated by logistic regression adjusting for confounders. Results The recurrence was 45% less likely with the use of one screw, independent of age, sex, additional technique, and preoperative HVA (odds ratio (ORadjusted) = 0.55 [95% CI 0.30–0.98], p = 0.043). The recurrence was 162% more likely with an additional surgical technique for HV (ORadjusted = 2.62 [1.24–5.52], p = 0.011). Conclusion In ReveL for HV, a single screw (instead of two screws) may be sufficient enough for a similar or even better outcome, which may also reduce costs. Additional surgical procedures for HV may be refrained from if possible. Due to limitations of a retrospective study, results may need validation with clinical trials.

Published
2018
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6. Imaging isodensity contours of molecular states with STM

Author

Gaël Reecht, Benjamin W Heinrich, Hervé Bulou, Fabrice Scheurer, Laurent Limot, and Guillaume Schull

Subjects
scanning tunneling microscopy, scanning tunneling spectroscopy, fulleren, C60, super-atomic orbitals, Science, Physics, QC1-999
Abstract

We present an improved way for imaging the density of states of a sample with a scanning tunneling microscope, which consists in mapping the surface topography while keeping the differential conductance (d I /d V ) constant. When archetypical C _60 molecules on Cu(111) are imaged with this method, these so-called iso-d I /d V maps are in excellent agreement with theoretical simulations of the isodensity contours of the molecular orbitals. A direct visualization and unambiguous identification of superatomic C _60 orbitals and their hybridization is then possible.

Published
2017
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7. Topologically localized excitons in single graphene nanoribbons

Author

Song Jiang, Tomáš Neuman, Alex Boeglin, Fabrice Scheurer, and Guillaume Schull

Subjects
Condensed Matter - Materials Science, Multidisciplinary, Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences
Abstract

Intrinsic optoelectronic properties of atomically precise graphene nanoribbons (GNRs) remain largely unexplored because of luminescence quenching effects that are due to the metallic substrate on which the ribbons are grown. We probed excitonic emission from GNRs synthesized on a metal surface with atomic-scale spatial resolution. A scanning tunneling microscope (STM)–based method to transfer the GNRs to a partially insulating surface was used to prevent luminescence quenching of the ribbons. STM-induced fluorescence spectra reveal emission from localized dark excitons that are associated with the topological end states of the GNRs. A low-frequency vibronic emission comb is observed and attributed to longitudinal acoustic modes that are confined to a finite box. Our study provides a path to investigate the interplay between excitons, vibrons, and topology in graphene nanostructures.

Published
2023
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8. Chest CT Findings and SARS-CoV-2 Infection in Trauma Patients-Is There a Prediction towards Higher Complication Rates?

Author

Fabrice Scheurer, Sascha Halvachizadeh, Till Berk, Hans-Christoph Pape, Roman Pfeifer, and University of Zurich

Subjects
10021 Department of Trauma Surgery, 610 Medicine & health, General Medicine, polytrauma, treatment strategy, CT thorax, SARS-CoV-2, trauma, outcome, pulmonary complications
Abstract

Background: Polytrauma patients with SARS-CoV-2 infections may be associated with an increased complication rate. The main goal of this study was to analyze the clinical course of trauma patients with COVID infection and a positive CT finding. Methods: This was a retrospective in-hospital study. Polytrauma patients diagnosed with SARS-CoV-2 infections were included in our analysis. The outcome parameters were pulmonary complication during admission, pulmonary embolism, pleural effusion, pneumonia, mortality, length of stay and readmission < 30 days. Results: 48 patients were included in the study. Trauma patients in the age-adjusted matched-pair analysis with typical changes in SARS-CoV-2 infection in CT findings showed significantly more pulmonary complications in general and significantly more cases of pneumonia (complications: 56% vs. 11%, p = 0.046; pneumonia 44% vs. 0%, p = 0.023). In addition, the clinical course of polytrauma patients with SARS-CoV-2 infection showed a high rate of pulmonary complications in the inpatient course (53%). Conclusion: The results of our study show that the changes in the CT findings of trauma patients with SARS-CoV-2 infection are a good indicator of further inpatient outcomes. Similarly, polytrauma patients with a SARS-CoV-2 infection and positive CT findings are shown to have increased risk for pulmonary complications.

Published
2022

9. Tip-induced excitonic luminescence nanoscopy of an atomically-resolved van der Waals heterostructure

Author

Luis E. Parra López, Anna Rosławska, Fabrice Scheurer, Stéphane Berciaud, and Guillaume Schull

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Mechanical Engineering, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, General Chemistry, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Condensed Matter::Materials Science, Mechanics of Materials, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Physics::Atomic and Molecular Clusters, General Materials Science, Optics (physics.optics), Physics - Optics
Abstract

Low-temperature scanning tunneling microscopy is used to probe, with atomic-scale spatial resolution, the intrinsic luminescence of a van der Waals heterostructure, made of a transition metal dichalcogenide monolayer stacked onto a few-layer graphene flake supported by an Au(111) substrate. Sharp emission lines arising from neutral, charged and localised excitons are reported. Their intensities and emission energies vary as a function of the nanoscale environment of the van der Waals heterostructure, explaining the variability of the emission properties observed with diffraction-limited approaches. Our work paves the way towards understanding and control of optoelectronic phenomena in moir\'e superlattices with atomic-scale resolution., Comment: 14 pages, 4 figures, 3 supplementary figures

Published
2022

10. Many-body description of STM-induced fluorescence of charged molecules

Author

Song Jiang, Tomáš Neuman, Rémi Bretel, Alex Boeglin, Fabrice Scheurer, Eric Le Moal, and Guillaume Schull

Subjects
Chemical Physics (physics.chem-ph), Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Chemical Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Physics and Astronomy, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences
Abstract

A scanning tunneling microscope is used to study the fluorescence of a model charged molecule (quinacridone) adsorbed on a sodium chloride (NaCl)-covered metallic sample. Fluorescence from the neutral and positively charged species is reported and imaged using hyper-resolved fluorescence microscopy. A many-body excitation model is established based on a detailed analysis of voltage, current and spatial dependencies of the fluorescence and electron transport features. This model reveals that quinacridone adopts a large palette of charge states, transient or not, depending on the voltage used and the nature of the underlying substrate. This model has a universal character and explains the electronic and fluorescence properties of many other molecules adsorbed on thin insulators.

Published
2022
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11. X-ray magnetic dichroism and tunnel magneto-resistance study of the magnetic phase in epitaxial CrVO

Author

Loïc, Joly, Fabrice, Scheurer, Philippe, Ohresser, Brice, Kengni-Zanguim, Jean-François, Dayen, Pierre, Seneor, Bruno, Dlubak, Florian, Godel, and David, Halley

Abstract

Epitaxial clusters of chromium and chromium-vanadium oxides are studied by tunnel magneto-resistivity measurements, x-ray absorption spectrometry and circular magnetic circular dichroism. They turn out to carry a small magnetic moment that follows a super-paramagnetic behavior. The chromium ion contribution to this magnetization is mainly due to an original magnetic Cr

Published
2021

12. Radiological and Clinical Outcome After Reversed L-Shaped Osteotomy: A Large Retrospective Swiss Cohort Study

Author

Jan Farei-Campagna, Katie Palmer, Stephan H. Wirth, Thorsten Jentzsch, Richard Niehaus, Marcel Deggeller, Fabrice Scheurer, Niklas Renner, University of Zurich, and Jentzsch, Thorsten

Subjects
Adult, Male, Reoperation, medicine.medical_specialty, medicine.medical_treatment, 610 Medicine & health, Osteotomy, 03 medical and health sciences, 2732 Orthopedics and Sports Medicine, 0302 clinical medicine, Recurrence, medicine, Humans, Orthopedics and Sports Medicine, Hallux Valgus, Aged, Retrospective Studies, 030222 orthopedics, biology, business.industry, Patient Selection, Retrospective cohort study, 030229 sport sciences, Odds ratio, Middle Aged, biology.organism_classification, 2746 Surgery, Surgery, Radiography, Valgus, Treatment Outcome, Patient Satisfaction, Radiological weapon, Orthopedic surgery, 10046 Balgrist University Hospital, Swiss Spinal Cord Injury Center, Female, Complication, business, Switzerland, Cohort study
Abstract

The objective was to report radiological and clinical outcomes after reversed L-shaped osteotomy (ReveL) for hallux valgus (HV). A retrospective cohort study was performed between January 2004 and December 2013. The primary outcome was radiological recurrence of HV (HV angle [HVA] >15°). There were various exposure and secondary outcome variables. The results showed a median follow-up of 12.0 months (N = 827). Radiological recurrence, limited patient satisfaction, complication, revision surgery, and elective hardware removal were found in 25.0%, 15.3%, 4.6%, 2.5%, and 26.7%. Median pre- to postoperative changes were highest for HVA (delta = –16.7°). Recurrence was more likely in cases with preoperative HVA ≥40° (adjusted odds ratio [ORadjusted]) 3.63, p

Published
2019
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13. Magnetic phase and magneto-resistive effects in vanadium oxide epitaxial nanoclusters

Author

Bohdan Kundys, Hicham Majjad, Corinne Ulhaq-Bouillet, D. Halley, Jean-Francois Dayen, Brice Kengni-Zanguim, Joseph Uzan, Philippe Ohresser, Fabrice Scheurer, Loïc Joly, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
010302 applied physics, Materials science, Physics and Astronomy (miscellaneous), Spintronics, Condensed matter physics, Vanadium, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Vanadium oxide, Nanoclusters, Condensed Matter::Materials Science, chemistry, Ferromagnetism, Phase (matter), 0103 physical sciences, Condensed Matter::Strongly Correlated Electrons, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, Superparamagnetism, Spin canting
Abstract

International audience; The metal-insulator transition and the original magnetic phase that appear in vanadium oxide nanoclusters epitaxially embedded in an MgO matrix are studied via electron transport, magneto-resistance, and X-ray circular dichroism measurements. The metal-insulator transition temperature is observed to be in the range of 1.5-27 K. We observe, from 0.3 K to at least 125 K, a superparamagnetic behavior, whereas vanadium oxide, in its bulk phase, is reported to be anti-ferromagnetic (AF) at low temperatures. This striking feature is consistent with either ferromagnetic spin pairing or spin canting in the AF spin order along the 1D vanadium ion chains of the Magn eli phase or for the VO 2 (A)-like phase. Finally, the observed magneto-resistive effect, which reached up to 8% at low temperatures, indicates ferromagnetic behavior for some of the nanoparticles. This enables their integration in spintronic devices that could be combined with metal-insulator switching and magneto-resistive effects.

Published
2020
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14. X-ray magnetic dichroism and tunnel magneto-resistance study of the magnetic phase in epitaxial CrVO x nanoclusters

Author

Loïc Joly, Fabrice Scheurer, Philippe Ohresser, Brice Kengni-Zanguim, Jean-François Dayen, Pierre Seneor, Bruno Dlubak, Florian Godel, and David Halley

Subjects
Condensed Matter::Strongly Correlated Electrons, General Materials Science, Physics::Atomic Physics, Condensed Matter Physics
Abstract

Epitaxial clusters of chromium and chromium–vanadium oxides are studied by tunnel magneto-resistivity measurements, x-ray absorption spectrometry and circular magnetic circular dichroism. They turn out to carry a small magnetic moment that follows a super-paramagnetic behavior. The chromium ion contribution to this magnetization is mainly due to an original magnetic Cr2O3-like phase, whereas usual Cr2O3 is known to be anti-ferromagnetic in the bulk. For mixed clusters, vanadium ions also contribute to the total magnetization and they are coupled to the chromium ion spins. By measuring the dichroic signal at different temperatures, we get insight into the possible spin configurations of vanadium and chromium ions: we propose that the magnetic dipoles observed in the clusters assembly could be related to ionic spins that couple at a very short range, as for instance in short one-dimensional spins chains.

Published
2022
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15. Ultralow-temperature device dedicated to soft X-ray magnetic circular dichroism experiments

Author

Philippe Ohresser, Florian Leduc, B. Gobaut, Giulia Serrano, B. Muller, Roberta Sessoli, Loïc Joly, Andrea Cornia, Matteo Mannini, M.-A. Arrio, Fabrice Scheurer, E. Lhotel, Guy Schmerber, Lorenzo Poggini, Edwige Otero, Weicheng Li, Jean-Paul Kappler, Ph. Sainctavit, Fadi Choueikani, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), CFD Lab [Montréal], Department of Mechanical Engineering [Montréal], McGill University = Université McGill [Montréal, Canada]-McGill University = Université McGill [Montréal, Canada], Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Magnétisme et Supraconductivité (MagSup ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Università degli Studi di Modena e Reggio Emilia (UNIMORE), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique

Subjects
Nuclear and High Energy Physics, Materials science, Absorption spectroscopy, Magnetism, Instrumentation, Astrophysics::High Energy Astrophysical Phenomena, 02 engineering and technology, Radiation, 010402 general chemistry, 01 natural sciences, law.invention, Optics, soft X-rays, law, ultralow-temperature, ComputingMilieux_MISCELLANEOUS, business.industry, Magnetic circular dichroism, XMCD, 021001 nanoscience & nanotechnology, Research Papers, Synchrotron, 0104 chemical sciences, Magnetic field, Beamline, magnetism, Physics::Accelerator Physics, [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], 0210 nano-technology, business
Abstract

A new ultralow-temperature setup dedicated to soft X-ray absorption spectroscopy and X-ray magnetic circular dichroism experiments is described. Two experiments, performed on the DEIMOS beamline (SOLEIL synchrotron), demonstrate the outstanding performances of this new platform, particularly with regard to the lowest achievable temperature under X-ray irradiation (T = 220 mK)., A new ultralow-temperature setup dedicated to soft X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD) experiments is described. Two experiments, performed on the DEIMOS beamline (SOLEIL synchrotron), demonstrate the outstanding performance of this new platform in terms of the lowest achievable temperature under X-ray irradiation (T = 220 mK), the precision in controlling the temperature during measurements as well as the speed of the cooling-down and warming-up procedures. Moreover, owing to the new design of the setup, the eddy-current power is strongly reduced, allowing fast scanning of the magnetic field in XMCD experiments; these performances lead to a powerful device for X-ray spectroscopies on synchrotron-radiation beamlines facilities.

Published
2018
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16. Magnetism and Accelerator-Based Light Sources : Proceedings of the 7th International School ‘‘Synchrotron Radiation and Magnetism’’, Mittelwihr (France), 2018

Author

Hervé Bulou, Loïc Joly, Jean-Michel Mariot, Fabrice Scheurer, Hervé Bulou, Loïc Joly, Jean-Michel Mariot, and Fabrice Scheurer

Subjects
Synchrotron radiation--Congresses, Magnetism--Congresses
Abstract

This open access book collects the contributions of the seventh school on Magnetism and Synchrotron Radiation held in Mittelwihr, France, from 7 to 12 October 2018. It starts with an introduction to the physics of modern X-ray sources followed by a general overview of magnetism. Next, light / matter interaction in the X-ray range is covered with emphasis on different types of angular dependence of X-ray absorption spectroscopy and scattering. In the end, two domains where synchrotron radiation-based techniques led to new insights in condensed matter physics, namely spintronics and superconductivity, are discussed. The book is intended for advanced students and researchers to get acquaintance with the basic knowledge of X-ray light sources and to step into synchrotron-based techniques for magnetic studies in condensed matter physics or chemistry.

Published
2021

17. The influence of obesity and gender on outcome after reversed L-shaped osteotomy for hallux valgus

Author

Katie Palmer, Thorsten Jentzsch, Jan Farei-Campagna, Stephan H. Wirth, Niklas Renner, Marcel Deggeller, Fabrice Scheurer, Richard Niehaus, University of Zurich, and Jentzsch, Thorsten

Subjects
Male, lcsh:Diseases of the musculoskeletal system, 2745 Rheumatology, Improvable patient satisfaction, Logistic regression, Postoperative Complications, 0302 clinical medicine, Radiological relapse, Weight loss, Interquartile range, Body mass index (BMI), Orthopedics and Sports Medicine, Valgus deformity, 030222 orthopedics, Hallux valgus deformity (HV), Osteotomy, Treatment Outcome, Patient Satisfaction, 10046 Balgrist University Hospital, Swiss Spinal Cord Injury Center, Female, medicine.symptom, Switzerland, Research Article, medicine.medical_specialty, 610 Medicine & health, Reversed L-shaped osteotomy (ReveL), Long plantar arm osteotomy, Young Adult, 03 medical and health sciences, 2732 Orthopedics and Sports Medicine, Sex Factors, Rheumatology, Internal medicine, medicine, Humans, Obesity, Hallux Valgus, Retrospective Studies, 030203 arthritis & rheumatology, business.industry, Gender, Retrospective cohort study, Odds ratio, medicine.disease, Confidence interval, Radiography, lcsh:RC925-935, business, Body mass index, Follow-Up Studies
Abstract

Background Hallux valgus deformity (HV) affects around every fourth individual, and surgical treatment is performed in every thousandth person. There is an ongoing quest for the best surgical management and reduction of undesirable outcomes. The aim was to explore associations of obesity and gender with radiological and clinical outcome after reversed L-shaped osteotomy (ReveL) for HV. Materials and methods This study was carried out in a retrospective cohort design at a single University Hospital in Switzerland between January 2004 and December 2013. It included adult patients treated with ReveL for HV. The primary exposure was body mass index (BMI) at the time of ReveL. The secondary exposure was gender. The primary outcome was radiological relapse of HV (HV angle [HVA] > 15 degrees [°]) at the last follow-up. Secondary outcomes were improvable patient satisfaction, complication, redo surgery, and optional hardware removal. Logistic regression analysis adjusted for confounders. Results The median weight, height, and BMI were 66.0 (interquartile range [IQR] 57.0–76.0) kilograms (kg), 1.65 (IQR 1.60–1.71) metres (m), and 24.0 (IQR 21.3–27.8) kg/m2. Logistic regression analysis did not show associations of relapse with BMI, independent of age, gender, additional technique, and preoperative HVA (adjusted odds ratio [ORadjusted] = 1.10 [95% (%) confidence interval (CI) = 0.70–1.45], p = 0.675). Relapse was 91% more likely in males (ORadjusted = 1.91 [95% CI = 1.19–3.06], p = 0.007). Improvable satisfaction was 79% more likely in males (ORadjusted = 1.79 [CI = 1.04–3.06], p = 0.035). Hardware removal was 47% less likely in males (ORadjusted = 0.53 [95% CI 0.30–0.94], p = 0.029). Conclusions In this study, obesity was not associated with unsatisfactory outcomes after ReveL for HV. This challenges the previous recommendation that preoperative weight loss may be necessary for a successful surgical treatment outcome. Males may be informed about potentially higher associations with unfavourable outcomes. Due to the risk of selection bias and lack of causality, findings may need to be confirmed with clinical trials.

Published
2019
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18. High Spin Polarization at Ferromagnetic Metal–Organic Interfaces: A Generic Property

Author

P. Wetzel, Wulf Wulfhekel, Loïc Joly, Amina Taleb-Ibrahimi, Manuel Gruber, Eric Beaurepaire, Dimitra Xenioti, Mebarek Alouani, Jacek Arabski, Fabrice Scheurer, Samar Hajjar-Garreau, Patrick Le Fèvre, Martin Bowen, François Bertran, Wolfgang Weber, Samy Boukari, Fatima Djeghloul, Hervé Bulou, G. Garreau, and E. Urbain

Subjects
Materials science, Spintronics, Spin polarization, Condensed matter physics, Generic property, Photoemission spectroscopy, Fermi level, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Condensed Matter::Materials Science, symbols.namesake, D band, Ferromagnetism, 0103 physical sciences, symbols, Molecule, Condensed Matter::Strongly Correlated Electrons, General Materials Science, Physical and Theoretical Chemistry, 010306 general physics, 0210 nano-technology
Abstract

A high spin polarization of states around the Fermi level, EF, at room temperature has been measured in the past at the interface between a few molecular candidates and the ferromagnetic metal Co. Is this promising property for spintronics limited to these candidates? Previous reports suggested that certain conditions, such as strong ferromagnetism, i.e., a fully occupied spin-up d band of the ferromagnet, or the presence of π bonds on the molecule, i.e., molecular conjugation, needed to be met. What rules govern the presence of this property? We have performed spin-resolved photoemission spectroscopy measurements on a variety of such interfaces. We find that this property is robust against changes to the molecule and ferromagnetic metal's electronic properties, including the aforementioned conditions. This affirms the generality of highly spin-polarized states at the interface between a ferromagnetic metal and a molecule and augurs bright prospects toward integrating these interfaces within organic spintronic devices.

Published
2016
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19. Electrofluorochromism at the single-molecule level

Author

Michael C. Chong, Guillaume Schull, Fabrice Scheurer, Hervé Bulou, Benjamin Doppagne, Alex Boeglin, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
FOS: Physical sciences, Insulator (electricity), 02 engineering and technology, Electroluminescence, 01 natural sciences, law.invention, Oxidation state, law, Physics - Chemical Physics, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Molecule, 010306 general physics, Plasmon, ComputingMilieux_MISCELLANEOUS, Chemical Physics (physics.chem-ph), [PHYS]Physics [physics], Multidisciplinary, Condensed Matter - Mesoscale and Nanoscale Physics, 021001 nanoscience & nanotechnology, Fluorescence, 3. Good health, Radical ion, Chemical physics, Scanning tunneling microscope, 0210 nano-technology
Abstract

The interplay between the oxidation state and the optical properties of molecules plays a key role for applications in displays, sensors or molecular-based memories. The fundamental mechanisms occurring at the level of a single-molecule have been difficult to probe. We used a scanning tunneling microscope (STM) to characterize and control the fluorescence of a single Zn-phthalocyanine radical cation adsorbed on a NaCl-covered Au(111) sample. The neutral and oxidized states of the molecule were identified on the basis of their fluorescence spectra that revealed very different emission energies and vibronic fingerprints. The emission of the charged molecule was controlled by tuning the thickness of the insulator and the plasmons localized at the apex of the STM tip. In addition, sub-nanometric variations of the tip position were used to investigate the charging and electroluminescence mechanisms., 11 pages, 4 figures

Published
2018
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20. Fano Description of Single-Hydrocarbon Fluorescence Excited by a Scanning Tunneling Microscope

Author

Jörg Kröger, Benjamin Doppagne, Fabrice Scheurer, Guillaume Schull, scheurer, fabrice, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Technische Universität Ilmenau (TU )

Subjects
Materials science, polyaromatic hydrocarbon, Exciton, FOS: Physical sciences, Bioengineering, 02 engineering and technology, 01 natural sciences, Molecular physics, law.invention, [PHYS.PHYS.PHYS-CHEM-PH] Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], law, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Fano, Physics::Atomic and Molecular Clusters, General Materials Science, Physics::Chemical Physics, 010306 general physics, STM-induced luminesence, Plasmon, Quantum tunnelling, Condensed Matter - Mesoscale and Nanoscale Physics, Mechanical Engineering, single-molecule fluorescence, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Single-molecule experiment, 3. Good health, Excited state, Light emission, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Scanning tunneling microscope, 0210 nano-technology, Luminescence
Abstract

The detection of fluorescence with submolecular resolution enables the exploration of spatially varying photon yields and vibronic properties at the single-molecule level. By placing individual polycyclic aromatic hydrocarbon molecules into the plasmon cavity formed by the tip of a scanning tunneling microscope and a NaCl-covered Ag(111) surface, molecular light emission spectra are obtained that unravel vibrational progression. In addition, light spectra unveil a signature of the molecule even when the tunneling current is injected well separated from the molecular emitter. This signature exhibits a distance-dependent Fano profile that reflects the subtle interplay between inelastic tunneling electrons, the molecular exciton and localized plasmons in at-distance as well as on-molecule fluorescence. The presented findings open the path to luminescence of a different class of molecules than investigated before and contribute to the understanding of single-molecule luminescence at surfaces in a unified picture., Comment: 24 pages, 4 figures

Published
2018
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21. The influence of the number of screws and additional surgical procedures on outcome in hallux valgus treatment

Author

Richard Niehaus, Katie Palmer, Fabrice Scheurer, Thorsten Jentzsch, Jan Farei-Campagna, Stephan H. Wirth, Niklas Renner, Marcel Deggeller, and University of Zurich

Subjects
Male, medicine.medical_specialty, lcsh:Diseases of the musculoskeletal system, medicine.medical_treatment, Bone Screws, 610 Medicine & health, Reversed L-shaped osteotomy (ReveL), Osteotomy, Hallux valgus (HV), Cohort Studies, Long plantar arm osteotomy, 03 medical and health sciences, 2732 Orthopedics and Sports Medicine, 0302 clinical medicine, Patient satisfaction, lcsh:Orthopedic surgery, Recurrence, Humans, Medicine, Orthopedic Procedures, Orthopedics and Sports Medicine, Hallux Valgus, Retrospective Studies, 030203 arthritis & rheumatology, 030222 orthopedics, biology, business.industry, Screws, Retrospective cohort study, Odds ratio, Middle Aged, biology.organism_classification, Confidence interval, 2746 Surgery, Surgery, lcsh:RD701-811, Valgus, Treatment Outcome, Orthopedic surgery, 10046 Balgrist University Hospital, Swiss Spinal Cord Injury Center, lcsh:RC925-935, business, Research Article, Follow-Up Studies, Cohort study
Abstract

Background Surgical treatment of hallux valgus (HV) is one of the major flagships of orthopedic surgeons. Due to relatively unsatisfactory radiological and clinical outcomes, the search for the best surgical technique and causes for unsatisfactory outcomes continues. The objective was to investigate associations of the number of screws and additional surgical techniques for HV with radiological and clinical outcome after reversed L-shaped osteotomy (ReveL). Methods A retrospective cohort study of adults from a single University Hospital between 2004 and 2013 was performed. The primary exposure was the number of screws (one vs two) used for osseous fixation after ReveL. The secondary exposure was an additional surgical technique for HV (e.g., Akin osteotomy). The primary outcome was a radiological recurrence of HV (HV angle (HVA) > 15°) at last follow-up. The secondary outcomes were limited patient satisfaction, complication, revision surgery, and elective hardware removal. Odds ratio (OR) and 95% confidence interval (CI) were estimated by logistic regression adjusting for confounders. Results The recurrence was 45% less likely with the use of one screw, independent of age, sex, additional technique, and preoperative HVA (odds ratio (ORadjusted) = 0.55 [95% CI 0.30–0.98], p = 0.043). The recurrence was 162% more likely with an additional surgical technique for HV (ORadjusted = 2.62 [1.24–5.52], p = 0.011). Conclusion In ReveL for HV, a single screw (instead of two screws) may be sufficient enough for a similar or even better outcome, which may also reduce costs. Additional surgical procedures for HV may be refrained from if possible. Due to limitations of a retrospective study, results may need validation with clinical trials.

Published
2018
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22. Linking Electronic Transport through a Spin Crossover Thin Film to the Molecular Spin State Using X-ray Absorption Spectroscopy Operando Techniques

Author

E. Urbain, Daniel Lacour, Michał Studniarek, Wulf Wulfhekel, Guy Schmerber, Alberto Riminucci, B. Gobaut, Ufuk Halisdemir, L. M. Kandpal, K. Katcko, Fadi Choueikani, Fabrice Scheurer, Martin Bowen, Jinjie Chen, Loïc Joly, Samy Boukari, F. Schleicher, Jacek Arabski, Eric Beaurepaire, Timo Frauhammer, Marie Hervé, Kuppusamy Senthil Kumar, Edwige Otero, Wolfgang Weber, Mario Ruben, Philippe Ohresser, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique

Subjects
operando measurements, Materials science, Spin states, Absorption spectroscopy, spin crossover thin film, FOS: Physical sciences, 02 engineering and technology, Applied Physics (physics.app-ph), 010402 general chemistry, 01 natural sciences, Spin crossover, Molecular film, Molecule, General Materials Science, Thin film, solid-state device, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], spintronics, [PHYS]Physics [physics], X-ray absorption spectroscopy, Spintronics, Physics - Applied Physics, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Chemical physics, 0210 nano-technology
Abstract

One promising route toward encoding information is to utilize the two stable electronic states of a spin crossover molecule. However, while this property is clearly manifested in transport across single molecule junctions, evidence linking charge transport across a solid-state device to the molecular film's spin state has thus far remained indirect. To establish this link, we deploy materials-centric and device-centric operando experiments involving X-ray absorption spectroscopy. We find a correlation between the temperature dependencies of the junction resistance and the Fe spin state within the device's Fe(bpz)2(phen) molecular film. We also factually observe that the Fe molecular site mediates charge transport. Our dual operando studies reveal that transport involves a subset of molecules within an electronically heterogeneous spin crossover film. Our work confers an insight that substantially improves the state-of-the-art regarding spin crossover-based devices, thanks to a methodology that can benefit device studies of other next-generation molecular compounds., Typo in the first name of one of the authors updated (Jinje -> Jinjie)

Published
2018
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23. Bright Electroluminescence from Single Graphene Nanoribbon Junctions

Author

Andrea Ferretti, Deborah Prezzi, Claudia Cardoso, Nasima Afsharimani, Fabrice Scheurer, Michael C. Chong, Guillaume Schull, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and scheurer, fabrice

Subjects
Materials science, Band gap, FOS: Physical sciences, Bioengineering, 02 engineering and technology, Substrate (electronics), Electroluminescence, 010402 general chemistry, 01 natural sciences, law.invention, electroluminescence, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Materials Science, Emission spectrum, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], density functional theory, GW-BSE, Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Graphene, business.industry, Mechanical Engineering, Graphene nanoribbons, Materials Science (cond-mat.mtrl-sci), Biasing, General Chemistry, scanning tunneling microscopy induced light emission, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, 3. Good health, Optoelectronics, single-molecule junction, Scanning tunneling microscope, 0210 nano-technology, business, [PHYS.COND] Physics [physics]/Condensed Matter [cond-mat]
Abstract

Thanks to their highly tunable band gaps, graphene nanoribbons (GNRs) with atomically precise edges are emerging as mechanically and chemically robust candidates for nanoscale light emitting devices of modulable emission color. While their optical properties have been addressed theoretically in depth, only few experimental studies exist, limited to ensemble measurements and without any attempt to integrate them in an electronic-like circuit. Here we report on the electroluminescence of individual GNRs suspended between the tip of a scanning tunneling microscope (STM) and a Au(111) substrate, constituting thus a realistic opto-electronic circuit. Emission spectra of such GNR junctions reveal a bright and narrow band emission of red light, whose energy can be tuned with the bias voltage applied to the junction, but always lying below the gap of infinite GNRs. Comparison with {\it ab initio} calculations indicate that the emission involves electronic states localized at the GNR termini. Our results shed light on unpredicted optical transitions in GNRs and provide a promising route for the realization of bright, robust and controllable graphene-based light emitting devices., Comment: Supporting Information avail on the ACS website at DOI: 10.1021/acs.nanolett.7b03797

Published
2018
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24. Cu Metal/Mn Phthalocyanine Organic Spinterfaces atop Co with High Spin Polarization at Room Temperature

Author

Samy Boukari, Jacek Arabski, Fatima Ibrahim, P. Le Fèvre, François Bertran, P. Wetzel, Martin Bowen, G. Garreau, Michał Studniarek, Eric Beaurepaire, Loïc Joly, E. Denys, Fabrice Scheurer, E. Urbain, Wolfgang Weber, F. Ngassam Nyakam, Mebarek Alouani, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique

Subjects
Materials science, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, Biomaterials, Metal, chemistry.chemical_compound, Condensed Matter::Materials Science, Spin crossover, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Electrochemistry, 010306 general physics, Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Spin polarization, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Condensed Matter Physics, 3. Good health, Electronic, Optical and Magnetic Materials, chemistry, visual_art, visual_art.visual_art_medium, Phthalocyanine, Physical chemistry, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology
Abstract

The organic spinterface describes the spin-polarized properties that develop, due to charge transfer, at the interface between a ferromagnetic metal (FM) and the molecules of an organic semiconductor. Yet, if the latter is also magnetic (e.g. molecular spin chains), the interfacial magnetic coupling can generate complexity within magnetotransport experiments. Also, assembling this interface may degrade the properties of its constituents (e.g. spin crossover or non-sublimable molecules). To circumvent these issues, one can separate the molecular and FM films using a less reactive nonmagnetic metal (NM). Spin-resolved photoemission spectroscopy measurements on the prototypical system Co(001)//Cu/Mnphthalocyanine (MnPc) reveal that the Cu/MnPc spinterface atop ferromagnetic Co is highly spin-polarized at room temperature, up to Cu spacer thicknesses of at least 10 monolayers. Ab-initio theory describes a spin polarization of the topmost Cu layer after molecular hybridization that can be accompanied by magnetic hardening effects. This spinterface's unexpected robustness paves the way for 1) integrating electronically fragile molecules within organic spinterfaces, and 2) manipulating molecular spin chains using the well-documented spin transfer torque properties of the FM/NM bilayer., Comment: 16 pages. Submitted

Published
2018
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25. Exchange bias and room-temperature magnetic order in molecular layers

Author

Fatima Ibrahim, Kai Chen, Manuel Gruber, Mebarek Alouani, Philippe Ohresser, Fadi Choueikani, Jinjie Chen, Victor Da Costa, Edwige Otero, V. Davesne, Fabrice Scheurer, Michał Studniarek, Eric Beaurepaire, Wulf Wulfhekel, Moritz Peter, Jacek Arabski, Hironari Isshiki, Hashim Jabbar, Ufuk Halisdemir, Martin Bowen, Loïc Joly, Samy Boukari, and Wolfgang Weber

Subjects
Materials science, Spintronics, Spin polarization, Condensed matter physics, Magnetism, Mechanical Engineering, General Chemistry, Condensed Matter Physics, Inductive coupling, Condensed Matter::Materials Science, Paramagnetism, Exchange bias, Ferromagnetism, Mechanics of Materials, Antiferromagnetism, Condensed Matter::Strongly Correlated Electrons, General Materials Science
Abstract

Molecular semiconductors may exhibit antiferromagnetic correlations well below room temperature. Although inorganic antiferromagnetic layers may exchange bias single-molecule magnets, the reciprocal effect of an antiferromagnetic molecular layer magnetically pinning an inorganic ferromagnetic layer through exchange bias has so far not been observed. We report on the magnetic interplay, extending beyond the interface, between a cobalt ferromagnetic layer and a paramagnetic organic manganese phthalocyanine (MnPc) layer. These ferromagnetic/organic interfaces are called spinterfaces because spin polarization arises on them. The robust magnetism of the Co/MnPc spinterface stabilizes antiferromagnetic ordering at room temperature within subsequent MnPc monolayers away from the interface. The inferred magnetic coupling strength is much larger than that found in similar bulk, thin or ultrathin systems. In addition, at lower temperature, the antiferromagnetic MnPc layer induces an exchange bias on the Co film, which is magnetically pinned. These findings create new routes towards designing organic spintronic devices.

Published
2015
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26. Highly spin-polarized carbon-based spinterfaces

Author

Eric Beaurepaire, Fabrice Scheurer, Wolfgang Weber, Samar Hajjar-Garreau, Wulf Wulfhekel, Jacek Arabski, Martin Bowen, F. Djeghloul, A. Taleb-Ibrahimi, P. Wetzel, Manuel Gruber, François Bertran, Samy Boukari, Loïc Joly, P. Le Fèvre, Hervé Bulou, G. Garreau, and Ali Hallal

Subjects
Materials science, Condensed matter physics, Spin polarization, Photoemission spectroscopy, chemistry.chemical_element, Nanotechnology, General Chemistry, law.invention, Condensed Matter::Materials Science, Carbon film, chemistry, Amorphous carbon, law, Physics::Atomic and Molecular Clusters, Chimie/Autre, Condensed Matter::Strongly Correlated Electrons, General Materials Science, Scanning tunneling microscope, Spectroscopy, Cobalt, Carbon
Abstract

We deploy topographical and spectroscopic techniques to show that a strongly spin-polarized interface arises between ferromagnetic cobalt and an amorphous carbon layer. Scanning tunneling microscopy and spectroscopy show how a semiconducting carbon film with a low band gap of about 0.4 eV is formed atop the metallic interface. To understand how the cobalt/carbon interface is formed, we used X-ray photoemission spectroscopy to study the hybridization state of carbon. We find that the semiconducting layer consists mainly of sp(2)-bonded carbon atoms with a sp(2)-to-sp(3) ratio between 1.4 and 1.8. The spin-polarized properties of the cobalt/carbon interface are studied by spin-resolved photoemission spectroscopy. We observe interface states close to the Fermi energy that are not exclusive to cobalt. These electronic states reveal a high degree of spin polarization at room temperature. (C) 2015 Elsevier Ltd. All rights reserved.

Published
2015
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27. Modulating the Ferromagnet/Molecule Spin Hybridization Using an Artificial Magnetoelectric

Author

Wolfgang Weber, Olivia Mauguin, Martin Bowen, Victor Da Costa, Michał Studniarek, Salia Cherifi-Hertel, Eric Beaurepaire, Guy Schmerber, Marie Hervé, Fadi Choueikani, Jacek Arabski, Charles-Henri Lambert, Cécile Marcelot, E. Urbain, Samy Boukari, Edwige Otero, Ludovic Largeau, Ufuk Halisdemir, Florian Leduc, Philippe Ohresser, Bénédicte Warot-Fonrose, Rémi Arras, F. Schleicher, Beata Taudul, Fabrice Scheurer, Wulf Wulfhekel, Loïc Joly, Abbass Hamadeh, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Matériaux et dispositifs pour l'Electronique et le Magnétisme (CEMES-MEM), Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Physikalisches Institut [Karlsruhe] (PHI), Karlsruher Institut für Technologie (KIT), Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies [Marcoussis] (C2N), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), and Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
X-ray absorption spectroscopy, Materials science, Condensed matter physics, Spintronics, Spin polarization, [PHYS.PHYS]Physics [physics]/Physics [physics], Magnetic circular dichroism, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Polarization (waves), 01 natural sciences, Ferroelectricity, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Biomaterials, Condensed Matter::Materials Science, Ferromagnetism, Electrochemistry, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Molecule, Condensed Matter::Strongly Correlated Electrons, [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], 0210 nano-technology
Abstract

International audience; Spin-polarized charge transfer at the interface between a ferromagnetic (FM)metal and a molecule can lead to ferromagnetic coupling and to a high spinpolarization at room temperature. The magnetic properties of these interfacescan not only alter those of the ferromagnet but can also stabilize molecularspin chains with interesting opportunities toward quantum computing. Withthe aim to enhance an organic spintronic device’s functionality, external controlover this spin polarization may thus be achieved by altering the ferromagnet/molecule interface’s magnetic properties. To do so, the magnetoelectricproperties of an underlying ferroelectric/ferromagnetic interface are utilized.Switching the ferroelectric polarization state of a PbZr0.2Ti0.8O3 (PZT) bottomlayer within a PZT/Co/FePc-based (Pc - phthalocyanine) device alters the X-raymagnetic circular dichroism of the Fe site within the phthalocyanine moleculartop layer. Thus, how to electrically alter the magnetic properties of an interfacewith high spin polarization at room temperature is demonstrated. Thisexpands electrical control over spin-polarized FM/molecule interfaces, which isfirst demonstrated using ferroelectric molecules, to all molecular classes.

Published
2017
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28. Vibronic Spectroscopy with Submolecular Resolution from STM-Induced Electroluminescence

Author

Fabrice Scheurer, Hervé Bulou, Alex Boeglin, Stéphane Berciaud, Michelangelo Romeo, Etienne Lorchat, Benjamin Doppagne, Michael C. Chong, Guillaume Schull, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), univOAK, Archive ouverte, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.MATE] Chemical Sciences/Material chemistry, Materials science, Resolution (electron density), General Physics and Astronomy, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Electroluminescence, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, Fluorescence, 3. Good health, law.invention, law, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Vibronic spectroscopy, Molecule, Scanning tunneling microscope, Atomic physics, Physics::Chemical Physics, 010306 general physics, 0210 nano-technology
Abstract

A scanning tunneling microscope is used to generate the electroluminescence of phthalocyanine molecules deposited on NaCl/Ag(111). Photon spectra reveal an intense emission line at approximate to 1.9 eV that corresponds to the fluorescence of the molecules, and a series of weaker redshifted lines. Based on a comparison with Raman spectra acquired on macroscopic molecular crystals, these spectroscopic features can be associated with the vibrational modes of the molecules and provide a detailed chemical fingerprint of the probed species. Maps of the vibronic features reveal submolecularly resolved structures whose patterns are related to the symmetry of the probed vibrational modes.

Published
2017
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29. Efficient Spin-Flip Excitation of a Nickelocene Molecule

Author

Benjamin Verlhac, Marie-Laure Bocquet, Loïc Joly, P. N. Abufager, Fabrice Scheurer, Philippe Ohresser, Marisa N. Faraggi, Laurent Limot, M. Ormaza, Nicolás Lorente, Michelangelo Romeo, N. Bachellier, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), scheurer, fabrice, Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional de Rosario [Argentina], CEA- Saclay (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centro de Fisica de Materiales (CFM), Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Donostia International Physics Center - DIPC (SPAIN), Donostia International Physics Center (DIPC), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU)-University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), limot, laurent, and Agence Nationale de la Recherche (France)

Subjects
inelastic electron tunneling spectroscopy, Magnetism, Ciencias Físicas, Bioengineering, 02 engineering and technology, 01 natural sciences, law.invention, [PHYS] Physics [physics], law, 0103 physical sciences, Atom, General Materials Science, 010306 general physics, Tip functionalization, Magnetic anisotropy, tip functionalization, density functional theory, Metallocene, [PHYS]Physics [physics], magnetic anisotropy, Magnetic moment, Inelastic electron tunneling spectroscopy, Chemistry, Magnetic circular dichroism, Mechanical Engineering, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, spin-flip, Density functional theory, X-ray magnetic circular dichroism, Atomic physics, Scanning tunneling microscope, Spin-flip, 0210 nano-technology, Excitation, CIENCIAS NATURALES Y EXACTAS, Física de los Materiales Condensados
Abstract

Inelastic electron tunneling spectroscopy (IETS) within the junction of a scanning tunneling microscope (STM) uses current-driven spin-flip excitations for an all-electrical characterization of the spin state of a single object. Usually decoupling layers between the single object, atom or molecule, and the supporting surface are needed to observe these excitations. Here we study the surface magnetism of a sandwich nickelocene molecule (Nc) adsorbed directly on Cu(100) by means of X-ray magnetic circular dichroism (XMCD) and density functional theory (DFT) calculations and show with IETS that it exhibits an exceptionally efficient spin-flip excitation. The molecule preserves its magnetic moment and magnetic anisotropy not only on Cu(100), but also in different metallic environments including the tip apex. By taking advantage of this robusteness, we are able to functionalize the microscope tip with a Nc, which can be employed as a portable source of inelastic excitations as exemplified by a double spin-flip excitation process., This work has been supported by the Agence Nationale de la Recherche (Grant Nos. ANR-13-BS10–0016, ANR-11-LABX-0058 NIE, ANR-10-LABX-0026 CSC).

Published
2017
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30. Une diode électroluminescente à une molécule

Author

Gaël Reecht, Guillaume Schull, and Fabrice Scheurer

Abstract

Un premier composant de taille moleculaire combinant des proprietes electroniques et photoniques a ete realise. Pour ce faire, un brin unique d’un polymere conducteur (polythiophene) a ete etire entre une surface metallique et la pointe effilee d’un microscope a effet tunnel (STM) fonctionnant a basse temperature (4K). Lorsqu’une tension de l’ordre de 2V est appliquee entre ces deux electrodes, le courant electrique traversant la molecule genere une emission de lumiere. Cette emission est liee a la recombinaison entre un electron injecte dans la molecule depuis la pointe avec un trou injecte depuis l’echantillon. Le mecanisme de luminescence ainsi que la dependance en tension de l’emission montre que la jonction se comporte comme une diode electroluminescente (LED) a une molecule.

Published
2014
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31. Ordinary and Hot Electroluminescence from Single-Molecule Devices: Controlling the Emission Color by Chemical Engineering

Author

Lydia Sosa-Vargas, Hervé Bulou, Michael C. Chong, Fabrice Mathevet, Guillaume Schull, Alex Boeglin, Fabrice Scheurer, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Chimie des polymères (LCP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
Microscope, Bioengineering, Astrophysics::Cosmology and Extragalactic Astrophysics, 02 engineering and technology, Electroluminescence, 01 natural sciences, law.invention, law, 0103 physical sciences, Molecule, [CHIM]Chemical Sciences, General Materials Science, Emission spectrum, 010306 general physics, Astrophysics::Galaxy Astrophysics, Quantum tunnelling, ComputingMilieux_MISCELLANEOUS, Chemistry, business.industry, Mechanical Engineering, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 3. Good health, Excited state, Optoelectronics, Scanning tunneling microscope, 0210 nano-technology, Luminescence, business
Abstract

Single-molecule junctions specifically designed for their optical properties are operated as light-emitting devices using a cryogenic scanning tunneling microscope. They are composed of an emitting unit—a molecular chromophore—suspended between a Au(111) surface and the tip of the microscope by organic linkers. Tunneling electrons flowing through these junctions generate a narrow-line emission of light whose color is controlled by carefully selecting the chemical structure of the emitting unit. Besides the main emission line, red and blue-shifted vibronic features of low intensity are also detected. While the red-shifted features provide a spectroscopic fingerprint of the emitting unit, the blue-shifted ones are interpreted in terms of hot luminescence from vibrationally excited states of the molecule.

Published
2016
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32. Simple and advanced ferromagnet/molecule spinterfaces

Author

F. Djedhloul, Fatima Ibrahim, Hashim Jabbar, Philippe Ohresser, Fabrice Scheurer, Kai Chen, Edwige Otero, Jacek Arabski, Clément Barraud, P. Le Fèvre, Richard Mattana, Samar Hajjar-Garreau, Wulf Wulfhekel, Samy Boukari, Ufuk Halisdemir, François Bertran, E. Urbain, Hironari Isshiki, Frédéric Petroff, Moritz Peter, Martin Bowen, Mebarek Alouani, Pierre Seneor, A. Taleb-Ibrahimi, P. Wetzel, Loïc Joly, Cyrile Deranlot, Michał Studniarek, Eric Beaurepaire, V. Da Costa, Fadi Choueikani, Stéphane Fusil, D. Xenioti, Hervé Bulou, G. Garreau, Jinjie Chen, Karim Bouzehouane, V. Davesne, Wolfgang Weber, and Manuel Gruber

Subjects
Materials science, Condensed matter physics, Spin polarization, Fermi level, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Organic semiconductor, Condensed Matter::Materials Science, symbols.namesake, Exchange bias, Ferromagnetism, Spin crossover, 0103 physical sciences, symbols, Antiferromagnetism, Condensed Matter::Strongly Correlated Electrons, 010306 general physics, 0210 nano-technology, Quantum tunnelling
Abstract

Spin-polarized charge transfer between a ferromagnet and a molecule can promote molecular ferromagnetism 1, 2 and hybridized interfacial states3, 4. Observations of high spin-polarization of Fermi level states at room temperature5 designate such interfaces as a very promising candidate toward achieving a highly spin-polarized, nanoscale current source at room temperature, when compared to other solutions such as half-metallic systems and solid-state tunnelling over the past decades. We will discuss three aspects of this research. 1) Does the ferromagnet/molecule interface, also called an organic spinterface, exhibit this high spin-polarization as a generic feature? Spin-polarized photoemission experiments reveal that a high spin-polarization of electronics states at the Fermi level also exist at the simple interface between ferromagnetic cobalt and amorphous carbon6. Furthermore, this effect is general to an array of ferromagnetic and molecular candidates7. 2) Integrating molecules with intrinsic properties (e.g. spin crossover molecules) into a spinterface toward enhanced functionality requires lowering the charge transfer onto the molecule8 while magnetizing it1,2. We propose to achieve this by utilizing interlayer exchange coupling within a more advanced organic spinterface architecture. We present results at room temperature across the fcc Co(001)/Cu/manganese phthalocyanine (MnPc) system9. 3) Finally, we discuss how the Co/MnPc spinterface’s ferromagnetism stabilizes antiferromagnetic ordering at room temperature onto subsequent molecules away from the spinterface, which in turn can exchange bias the Co layer at low temperature10. Consequences include tunnelling anisotropic magnetoresistance across a CoPc tunnel barrier11. This augurs new possibilities to transmit spin information across organic semiconductors using spin flip excitations12.

Published
2016
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33. Interface Magnetoelectric Coupling in Co/Pb(Zr,Ti)O3

Author

Gervasi Herranz, Matthieu Jamet, Salia Cherifi-Hertel, Riccardo Hertel, Philippe Ohresser, Bénédicte Warot-Fonrose, Rémi Arras, L. Calmels, Cécile Marcelot, Romain Jarrier, Fabrice Scheurer, Ondřej Vlašín, Agence Nationale de la Recherche (France), Ministerio de Economía y Competitividad (España), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Matériaux et dispositifs pour l'Electronique et le Magnétisme (CEMES-MEM), Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Interférométrie, In situ et Instrumentation pour la Microscopie Electronique (CEMES-I3EM), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, ANR-11-JS10-0009,DYNAMECS,Processus dynamiques dans des matériaux magnétoélectriques(2011), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), THALES [France]-Centre National de la Recherche Scientifique (CNRS), and THALES-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Materials science, Magnetic structure, Condensed matter physics, Magnetic circular dichroism, Electro-optic effect, Magnetoelectric effect, 02 engineering and technology, 021001 nanoscience & nanotechnology, Interface-mediated coupling, 01 natural sciences, Magnetization, Nuclear magnetic resonance, Artificial multiferroics, Transmission electron microscopy, Electric field, 0103 physical sciences, Magneto-optic effect, Magnetoelectrics, General Materials Science, Multiferroics, Density functional theory, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 0210 nano-technology
Abstract

Vlašín, Ondřej et al., Magnetoelectric coupling at multiferroic interfaces is a promising route toward the nonvolatile electric-field control of magnetization. Here, we use optical measurements to study the static and dynamic variations of the interface magnetization induced by an electric field in Co/ PbZr0.2Ti0.8O3 (Co/PZT) bilayers at room temperature. The measurements allow us to identify different coupling mechanisms. We further investigate the local electronic and magnetic structure of the interface by means of transmission electron microscopy, soft X-ray magnetic circular dichroism, and density functional theory to corroborate the coupling mechanism. The measurements demonstrate a mixed linear and quadratic optical response to the electric field, which results from a magneto-electto-optical effect. We propose a decomposition method of the optical signal to discriminate between different components involved in the electric field-induced polarization rotation of the reflected light. This allows us to extract a signal that we can ascribe to interface magnetoelectric coupling. The associated surface magnetization exhibits a clear hysteretic variation of odd symmetry with respect to the electric field and nonzero remanence. The interface coupling is remarkably stable over a wide frequency range (1-50 kHz), and the application of a bias magnetic field is not necessary for the coupling to occur. These results show the potential of exploiting interface coupling with the prospect of optimizing the performance of magnetoelectric memory devices in terms of stability, as well as fast and dissipationless operation., This work is supported by the French National Research Agency (ANR) through JCJC program "DYNAMECS” ANR-11-JS10-009-01 and the TEM study was conducted in the framework of project "EMMA” ANR-12-BS10-013. Financial support by the Spanish Government for the CSIC JAE-predoc grant of O.V. is acknowledged. S. C.-H. acknowledges the technical assistance of J.-S. Pelle (IPHC, Strasbourg) and the team of the STnano cleanroom facility in Strasbourg for the optimization of the magnetoelectric micro-devices. R. Cours (CEMES, Toulouse) is acknowledged for his help with the preparation of the sample lamellas for TEM measurements.

Published
2016
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34. Single molecules as whispering galleries for electrons

Author

Gaël Reecht, Hervé Bulou, Guillaume Schull, and Fabrice Scheurer

Subjects
Physics, business.industry, Physics::Optics, Elementary particle, 02 engineering and technology, Electron, Fermion, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Whispering, 01 natural sciences, Computational physics, Optics, 0103 physical sciences, Molecule, General Materials Science, Whispering-gallery wave, 010306 general physics, 0210 nano-technology, business, Sound wave, Lepton
Abstract

Whispering gallery modes, well-known for acoustic and optical waves, have been shown recently for electrons in molecules on surfaces. The existence of such waves opens new possibilities for nanoelectronic devices. Here we propose a simple analytical textbook model which allows the main characteristic features of such electronic waves to be understood. The model is illustrated by two- and three-dimensional experimental situations.

Published
2016

35. Low-Temperature Surface Diffusion on Metallic Surfaces

Author

Stefan Stanescu, Fabrice Scheurer, Philippe Ohresser, Emilie Gaudry, Christine Boeglin, Hervé Bulou, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Surface diffusion, Condensed matter physics, Magnetic circular dichroism, Chemistry, Diffusion, Monte Carlo method, Time evolution, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Metal, Condensed Matter::Materials Science, General Energy, visual_art, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], visual_art.visual_art_medium, Physical and Theoretical Chemistry, 010306 general physics, 0210 nano-technology, Quantum tunnelling, Line (formation)
Abstract

International audience; We present a study of the atomic surface diffusion at low temperature of Cr adatoms deposited on Cu(100), Cu(111), and Au(111) surfaces. Time-dependent X-ray magnetic circular dichroism (XMCD), Monte Carlo simulations, and the Kimball−Shortley iterative method are used to evidence a mechanism of quantum tunneling involved in the Cr adatom surface diffusion at temperatures below 40 K. We show that the XMCD line shape is correlated to the atomic configuration of Cr deposited on a metallic surface. A diffusion rate ranging from 0.03 Hz for Cu(100) to 30 Hz for Au(111) at 10 K is reported from the time evolution of the XMCD line shape. A quantum equation of motion for the Cr adatom is derived and solved by using a Kimball−Shortley iterative method. Good agreement between the calculated Bohr periods and the experimental diffusion rates is reported.

Published
2009
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36. Spin-Dependent Hybridization between Molecule and Metal at Room Temperature through Interlayer Exchange Coupling

Author

Fatima Ibrahim, Manuel Gruber, Martin Bowen, Michał Studniarek, Eric Beaurepaire, Hironari Isshiki, Fabrice Scheurer, Samy Boukari, Hashim Jabbar, Moritz Peter, Edwige Otero, Victor Da Costa, Wulf Wulfhekel, Jacek Arabski, Loïc Joly, Kai Chen, Philippe Ohresser, Wolfgang Weber, Mebarek Alouani, Fadi Choueikani, and V. Davesne

Subjects
Condensed matter physics, Spintronics, Magnetism, Chemistry, Mechanical Engineering, Fermi level, Aucun, Bioengineering, General Chemistry, Condensed Matter Physics, Inductive coupling, symbols.namesake, Paramagnetism, Magnetization, Condensed Matter::Materials Science, Nuclear magnetic resonance, Ab initio quantum chemistry methods, symbols, Density of states, General Materials Science, Condensed Matter::Strongly Correlated Electrons
Abstract

We experimentally and theoretically show that the magnetic coupling at room temperature between paramagnetic Mn within manganese phthalocyanine molecules and a Co layer persists when separated by a Cu spacer. The molecule's magnetization amplitude and direction can be tuned by varying the Cu-spacer thickness and evolves according to an interlayer exchange coupling mechanism. Ab initio calculations predict a highly spin-polarized density of states at the Fermi level of this metal-molecule interface, thereby strengthening prospective spintronics applications.

Published
2015

37. Pulling and Stretching a Molecular Wire to Tune its Conductance

Author

Hervé Bulou, Guillaume Schull, Gaël Reecht, Fabrice Scheurer, Fabrice Mathevet, Virginie Speisser, César González, Yannick J. Dappe, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), This work was performed using HPC resources from GENCI-TGCC (Grant no. 2014096813) and GENCI-IDRIS (Grantno. 2014092291), ANR-14-CE26-0016,SMAL'LED,Nano-composants electroluminescents à base de molecules uniques(2014), ANR-11-LABX-0058,NIE,Nanostructures en Interaction avec leur Environnement(2011), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), and Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Microscope, Molecular junction, Condensed Matter - Mesoscale and Nanoscale Physics, Chemistry, Ab initio, Conductance, FOS: Physical sciences, Nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Molecular physics, law.invention, Molecular wire, chemistry.chemical_compound, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Polythiophene, General Materials Science, Physical and Theoretical Chemistry, Current (fluid), Quantum tunnelling
Abstract

International audience; A scanning tunnelling microscope is used to pull a polythiophene wire from a Au(111) surface while measuring the current traversing the junction. Abrupt current increases measured during the lifting procedure are associated with the detachment of molecular subunits, in apparent contradiction with the expected exponential decrease of the conductance with wire length. Ab initio simulations reproduce the experimental data and demonstrate that this unexpected behavior is due to release of mechanical stress in the wire, paving the way to mechanically gated single-molecule electronic devices.

Published
2015
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38. Narrow-line single-molecule transducer between electronic circuits and surface plasmons

Author

Hervé Bulou, Alex Boeglin, Gaël Reecht, Guillaume Schull, Fabrice Scheurer, Michael C. Chong, Fabrice Mathevet, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Chimie des polymères (LCP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut Parisien de Chimie Moléculaire (IPCM), Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Exciton, Aucun, General Physics and Astronomy, FOS: Physical sciences, Nanotechnology, 02 engineering and technology, 01 natural sciences, law.invention, Laser linewidth, Molecular wire, law, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), [CHIM]Chemical Sciences, 010306 general physics, ComputingMilieux_MISCELLANEOUS, Plasmon, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Surface plasmon, 021001 nanoscience & nanotechnology, Transducer, Optoelectronics, Scanning tunneling microscope, 0210 nano-technology, business, Excitation
Abstract

A molecular wire containing an emitting molecular center is controllably suspended between the plasmonic electrodes of a cryogenic scanning tunneling microscope. Passing current through this circuit generates an ultranarrow-line emission at an energy of approximate to 1.5 eV which is assigned to the fluorescence of the molecular center. Control over the linewidth is obtained by progressively detaching the emitting unit from the surface. The recorded spectra also reveal several vibronic peaks of low intensities that can be viewed as a fingerprint of the emitter. Surface plasmons localized at the tip-sample interface are shown to play a major role in both excitation and emission of the molecular excitons.

Published
2015
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39. Magnetism and Synchrotron Radiation: Towards the Fourth Generation Light Sources : Proceedings of the 6th International School “Synchrotron Radiation and Magnetism”, Mittelwihr (France), 2012

Author

Eric Beaurepaire, Hervé Bulou, Loic Joly, Fabrice Scheurer, Eric Beaurepaire, Hervé Bulou, Loic Joly, and Fabrice Scheurer

Subjects
Synchrotron radiation--Congresses, Magnetism--Congresses
Abstract

Advances in the synthesis of new materials with often complex, nano-scaled structures require increasingly sophisticated experimental techniques that can probe the electronic states, the atomic magnetic moments and the magnetic microstructures responsible for the properties of these materials.At the same time, progress in synchrotron radiation techniques has ensured that these light sources remain a key tool of investigation, e.g. synchrotron radiation sources of the third generation are able to support magnetic imaging on a sub-micrometer scale.With the Sixth Mittelwihr School on Magnetism and Synchrotron Radiation the tradition of teaching the state-of-the-art on modern research developments continues and is expressed through the present set of extensive lectures provided in this volume. While primarily aimed at postgraduate students and newcomers to the field, this volume will also benefit researchers and lecturers actively working in the field.

Published
2013

40. Probing a Device's Active Atoms

Author

E. Urbain, Charles-Henri Lambert, Martin Bowen, Olivia Zill, Michel Hehn, Daniel Lacour, Anant Dixit, Samy Boukari, Loïc Joly, Sébastien Petit-Watelot, Pierre André Guitard, Michał Studniarek, Abbass Hamadeh, Marie Hervé, Jacek Arabski, Eric Beaurepaire, Philippe Ohresser, Wulf Wulfhekel, Wolfgang Weber, Fadi Choueikani, F. Schleicher, Guy Schmerber, Elmer Monteblanco, Fabrice Scheurer, Edwige Otero, Beata Taudul, François Montaigne, Mebarek Alouani, Manuel Acosta, Ufuk Halisdemir, Victor Da Costa, Florian Leduc, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Facultad de CC Economicas y Empresariales, Universidad de Cádiz (UCA), Dispositifs et Instrumentation en Optoélectronique et micro-ondes (DIOM), Université Jean Monnet [Saint-Étienne] (UJM), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Mikrostrukturphysik (MPI-HALLE), Max-Planck-Gesellschaft, Department of Information, Documentation and Communication, State Institute for Schools, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université Jean Monnet - Saint-Étienne (UJM), and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photon, Materials science, Absorption spectroscopy, Spintronics, business.industry, Mechanical Engineering, Heterojunction, 02 engineering and technology, Photon energy, 021001 nanoscience & nanotechnology, 01 natural sciences, 7. Clean energy, Tunnel magnetoresistance, Optics, Mechanics of Materials, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, Optoelectronics, Microelectronics, General Materials Science, 010306 general physics, 0210 nano-technology, business, Absorption (electromagnetic radiation)
Abstract

International audience; Devices studies are often augmented by separately conducted materials science studies to achieve better insight into device operation [1–4]. In one such materials science technique called X-ray absorption spectroscopy (XAS), the energy of soft X-ray photons is tuned so as to drive core level excitations of a specific atomic species within the sample (see Figure 1a). The resulting absorption spectrum yields information on the quantity and charge state of these atoms present, on their chemical environment and their resulting electronic/magnetic properties. When applied using the brilliance of a synchrotron facility, this technique is sensitive to minute populations of atoms, even when buried within a heterostructure. Resolving the properties of these atoms within a device built from this heterostruc-ture is in turn interpreted as providing insight into the device's performance. [2,5] As an important refinement, operando studies [6–12] alter the device's state (e.g., Materials science and device studies have, when implemented jointly as " operando " studies, better revealed the causal link between the properties of the device's materials and its operation, with applications ranging from gas sensing to information and energy technologies. Here, as a further step that maximizes this causal link, the paper focuses on the electronic properties of those atoms that drive a device's operation by using it to read out the materials property. It is demonstrated how this method can reveal insight into the operation of a macroscale, industrial-grade microelectronic device on the atomic level. A magnetic tunnel junction's (MTJ's) current, which involves charge transport across different atomic species and interfaces, is measured while these atoms absorb soft X-rays with synchrotron-grade brilliance. X-ray absorption is found to affect magnetotransport when the photon energy and linear polarization are tuned to excite FeO bonds parallel to the MTJ's interfaces. This explicit link between the device's spintronic performance and these FeO bonds, although predicted, challenges conventional wisdom on their detrimental spintronic impact. The technique opens interdisciplinary possibilities to directly probe the role of different atomic species on device operation, and shall considerably simplify the materials science iterations within device research.

Published
2017
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41. Validation of an Arthroscopic Training Device

Author

Samy Bouaicha, Fabrice Scheurer, Stefan Rahm, and Thorsten Jentzsch

Subjects
Adult, Male, medicine.medical_specialty, Demographics, Attitude of Health Personnel, Successful completion, Task (project management), Arthroscopy, Young Adult, 03 medical and health sciences, 0302 clinical medicine, Humans, Medicine, Orthopedics and Sports Medicine, Simulation Training, 030222 orthopedics, Rubber ring, medicine.diagnostic_test, business.industry, Training (meteorology), Construct validity, Test (assessment), 030220 oncology & carcinogenesis, Physical therapy, Female, Clinical Competence, business
Abstract

Purpose To investigate the usefulness and conduct validation of a simulated arthroscopy training device to train basic arthroscopy skills. Methods Forty-six participants including 12 novices, 12 intermediates, and 22 experts completed a questionnaire regarding demographics, previous arthroscopic experience, training potential, and statements about the device. Furthermore, participants performed a single task on the arthroscopic training device using the 0° camera and a probe. The task consisted of an attempt to carry a rubber ring across a helix inside a box as fast as possible. Construct validity was evaluated by comparing total task time and portal replacements of the camera and probe between all groups (median values [interquartile range]; Kruskal-Wallis test). Results The median age was 35 (29-44) years. There were 4 female and 42 male participants. A total of 89% of the participants graded the overall training capacity ≥5 (35% graded it as 5, 39% as 6, and 15% as 7), and 83% believed that it is useful to improve any kind of arthroscopy. Ninety-three percent of the participants would recommend the arthroscopic training device to their colleagues. Sixty-one percent of the participants stated that there are certain disadvantages. The median time to complete the task was 108 (58-236) seconds. Novices (259 [123-435] seconds) performed tasks significantly slower than intermediates (169 [67-257] seconds) and experts (75 [49-132] seconds) ( P = .005). Furthermore, portal changes were significantly more common in novices and intermediates than experts ( P = .019). Conclusions High scores in training potential were achieved with this arthroscopy simulator box, and most study participants believed that practice with the arthroscopic training device is useful for any kind of arthroscopy. Construct validity was established since novices, intermediates, and experts in real arthroscopy were discriminated with the arthroscopic training device in terms of time to successful completion of a task. However, 61% of the participants stated that there were certain disadvantages. Clinical Relevance In every training tool using simulation, it is crucial to pass the first steps in the validation cascade. This study provides this step for further evaluation of this arthroscopic training device.

Published
2017
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42. Chemical control of electrical contact to sp(2) carbon atoms

Author

Guillaume Schull, Thomas Frederiksen, Giuseppe Foti, Virginie Speisser, Fabrice Scheurer, European Commission, Eusko Jaurlaritza, Ministerio de Economía y Competitividad (España), Agence Nationale de la Recherche (France), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), and ANR-13-BS10-0016,SPINCOMM,Transport de spin dans un fil organométallique modulable(2013)

Subjects
Multidisciplinary, Nanostructure, Materials science, General Physics and Astronomy, chemistry.chemical_element, Nanotechnology, General Chemistry, Chimie/Chimie théorique et/ou physique, Atomic units, General Biochemistry, Genetics and Molecular Biology, Electrical contacts, Article, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry, Chemical physics, Electrode, Atom, Molecule, Electric current, Carbon
Abstract

This work is licensed under a Creative Commons Attribution 3.0 Unported License., Carbon-based nanostructures are attracting tremendous interest as components in ultrafast electronics and optoelectronics. The electrical interfaces to these structures play a crucial role for the electron transport, but the lack of control at the atomic scale can hamper device functionality and integration into operating circuitry. Here we study a prototype carbon-based molecular junction consisting of a single C 60 molecule and probe how the electric current through the junction depends on the chemical nature of the foremost electrode atom in contact with the molecule. We find that the efficiency of charge injection to a C 60 molecule varies substantially for the considered metallic species, and demonstrate that the relative strength of the metal-C bond can be extracted from our transport measurements. Our study further suggests that a single-C 60 junction is a basic model to explore the properties of electrical contacts to meso-and macroscopic sp 2 carbon structures. © 2014 Macmillan Publishers Limited., T.F. and G.F. acknowledge the support of the Basque Departamento de Educación and the UPV/EHU (Grant No. IT-756-13), the Spanish Ministerio de Economía y Competitividad (Grant No. FIS2010-19609-CO2-00) and the European Union Integrated Project PAMS. F.S. and G.S. acknowledge the Agence National de la Recherche for financial support (Contracts TRANSMOL ANR-2010-JCJC-1004 and SPINCOMM ANR-13-BS10-0016).

Published
2014
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43. Electroluminescence of a Polythiophene Molecular Wire Suspended between a Metallic Surface and the Tip of a Scanning Tunneling Microscope

Author

Virginie Speisser, Gaël Reecht, Fabrice Scheurer, Yannick J. Dappe, Guillaume Schull, and Fabrice Mathevet

Subjects
Materials science, Polarity (physics), business.industry, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, 02 engineering and technology, Electroluminescence, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, Fluorescence, law.invention, Molecular wire, chemistry.chemical_compound, chemistry, law, 0103 physical sciences, OLED, Optoelectronics, Polythiophene, Scanning tunneling microscope, 010306 general physics, 0210 nano-technology, business, Plasmon
Abstract

The electroluminescence of a polythiophene wire suspended between a metallic surface and the tip of a scanning tunneling microscope is reported. Under positive sample voltage, the spectral and voltage dependencies of the emitted light are consistent with the fluorescence of the wire junction mediated by localized plasmons. This emission is strongly attenuated for the opposite polarity. Both emission mechanism and polarity dependence are similar to what occurs in organic light emitting diodes (OLED) but at the level of a single molecular wire.

Published
2014
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44. Size-induced enhanced magnetoelectric effect and multiferroicity in chromium oxide nanoclusters

Author

D. Halley, Yves Henry, Hicham Majjad, Stéphane Berciaud, Bernard Doudin, Philippe Ohresser, N. Najjari, Fabrice Scheurer, Loïc Joly, and Corinne Ulhaq-Bouillet

Subjects
Multidisciplinary, Materials science, Aucun, Magnetoelectric effect, Chromium oxide, General Physics and Astronomy, Multiferroics, Nanotechnology, General Chemistry, General Biochemistry, Genetics and Molecular Biology, Nanoclusters
Abstract

The control of the magnetization of a material with an electric field would make the design and the integration of novel electronic devices possible. This explains the renewed interest in multiferroic materials. Progress in this field is currently hampered by the scarcity of the materials available and the smallness of the magnetoelectric effects. Here we present a proof-of-principle experiment showing that engineering large strains through nanoscale size reduction is an efficient route for increasing magnetoelectric coefficients by orders of magnitude. The archetype magnetoelectric material, Cr2O3, in the form of epitaxial clusters, exhibits an unprecedented 600% change in magnetization magnitude under 1V. Furthermore, a multiferroic phase, with both magnetic and electric spontaneous polarizations, is found in the clusters, while absent in the bulk. We gratefully acknowledge A. Carvalho for SEM observations, J. Arabski for technical assistance during MBE growth, STnano staff for technical support during microfabrication, B. Muller for technical support while setting up DEIMOS beamline, DEIMOS beamline staff for help during synchrotron experiments, and M. Bailleul and V. Da Costa for magnetic and structural characterization measurements. N.N. thanks Région Alsace for financial support.

Published
2014
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45. Direct observation of a highly spin-polarized organic spinterface at room temperature

Author

Riccardo Bertacco, Amina Taleb-Ibrahimi, Samy Boukari, Christian Rinaldi, Wolfgang Weber, S. Javaid, P. Le Fèvre, Eric Beaurepaire, Fatima Ibrahim, Richard Mattana, François Bertran, Mebarek Alouani, Philippe Ohresser, J. Arabski, Pierre Seneor, N. B. Brookes, Loïc Joly, F. Djeghloul, T. Miyamachi, J. P. Kappler, Pardeep K. Thakur, Martin Bowen, A. Jaafar, Fabrice Scheurer, Wulf Wulfhekel, Matteo Cantoni, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Politecn Milan, LNESS Dipartimento Fis, I-22100 Como, Italy, Paul Scherrer Inst, CH-5232 Villigen, Switzerland, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), European Synchrotron Radiation Facility (ESRF), Karlsruhe Inst Technol, Ctr Funct Nanostruct, D-76131 Karlsruhe, Germany, Karlsruhe Inst Technol, Inst Phys, D-76131 Karlsruhe, Germany, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, Université Paris-Sud - Paris 11 (UP11), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique

Subjects
Aucun, Electron, 02 engineering and technology, 7. Clean energy, 01 natural sciences, chemistry.chemical_compound, Organic spintronics, Electronic circuit, Spin-½, [PHYS]Physics [physics], Spin-polarized photoemission spectroscopy, Condensed Matter - Materials Science, Multidisciplinary, Condensed matter physics, Spin polarization, Magnetic moment, Applied Mathematics, Physics, Spin-polarized interface states, Computer Science Applications1707 Computer Vision and Pattern Recognition, Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials, Condensed Matter Physics, Current source, 021001 nanoscience & nanotechnology, Thermal conduction, Chemical physics, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology, Materials science, FOS: Physical sciences, Article, Condensed Matter::Materials Science, Atomic orbital, 0103 physical sciences, Electronic, Molecule, ddc:530, Optical and Magnetic Materials, Spin (physics), 010306 general physics, Spintronics, business.industry, Materials Science (cond-mat.mtrl-sci), Organic semiconductor, Semiconductor, Ferromagnetism, chemistry, Phthalocyanine, business
Abstract

International audience; Organic semiconductors constitute promising candidates toward large-scale electronic circuits that are entirely spintronics-driven. Toward this goal, tunneling magnetoresistance values above 300% at low temperature suggested the presence of highly spin-polarized device interfaces. However, such spinterfaces have not been observed directly, let alone at room temperature. Thanks to experiments and theory on the model spinterface between phthalocyanine molecules and a Co single crystal surface, we clearly evidence a highly efficient spinterface. Spin-polarised direct and inverse photoemission experiments reveal a high degree of spin polarisation at room temperature at this interface. We measured a magnetic moment on the molecule's nitrogen p orbitals, which substantiates an ab-initio theoretical description of highly spin-polarised charge conduction across the interface due to differing spinterface formation mechanisms in each spin channel. We propose, through this example, a recipe to engineer simple organic-inorganic interfaces with remarkable spintronic properties that can endure well above room temperature

Published
2013
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46. Oligothiophene Nanorings as Electron Resonators for Whispering Gallery Modes

Author

Virginie Speisser, Fabrice Scheurer, Guillaume Schull, Bernard Carrière, Gaël Reecht, Hervé Bulou, and Fabrice Mathevet

Subjects
Quantum optics, Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, business.industry, Nanowire, FOS: Physical sciences, General Physics and Astronomy, Electron, law.invention, Resonator, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Ribbon, Optoelectronics, Periodic boundary conditions, Scanning tunneling microscope, Whispering-gallery wave, business
Abstract

Structural and electronic properties of oligothiophene nano-wires and rings synthesized on a Au(111) surface are investigated by scanning tunneling microscopy. The spectroscopic data of the linear and cyclic oligomers show remarkable differences which, to a first approximation, can be accounted by considering electronic states confinement to one-dimensional (1D) boxes having respectively fixed and periodic boundary conditions. A more detailed analysis shows that polythiophene must be treated as a ribbon (i.e. having an effective width) rather than a purely 1D structure. A fascinating consequence is that the molecular nano-rings act as whispering gallery mode resonators for electrons, opening the way for new applications in quantum-electronics., Comment: 4 pages with 4 figures, To be published in Physical Review Letters

Published
2013
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47. Thermodynamics versus kinetics in a morphology transition of nanoparticles

Author

N. Moreau, Hervé Bulou, Christine Goyhenex, Virginie Speisser, Philippe Ohresser, Jérôme Lagoute, Fabrice Scheurer, Michelangelo Romeo, S. Rousset, Yann Girard, C. Chacon, B. Carrière, V. Repain, Edwige Otero, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire Matériaux et Phénomènes Quantiques (MPQ (UMR_7162)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Département Mécanismes d'Accidents (INRETS/MA), Institut National de Recherche sur les Transports et leur Sécurité (INRETS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Knoop, Martina, École normale supérieure - Paris (ENS Paris), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP)

Subjects
[PHYS]Physics [physics], Materials science, Thermodynamic equilibrium, Bilayer, chemistry.chemical_element, Thermodynamics, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, [PHYS] Physics [physics], Condensed Matter::Materials Science, chemistry, Picosecond, 0103 physical sciences, Atom, Monolayer, Physics::Atomic and Molecular Clusters, Stress relaxation, Cluster (physics), 010306 general physics, 0210 nano-technology, Palladium
Abstract

The morphology of cobalt, palladium, and platinum nanoclusters grown on a gold surface is analyzed from both thermodynamic and kinetic viewpoints. Although the thermodynamic equilibrium shape as a function of cluster size is similar for all three elements and shows a morphology transition from monolayer to bilayer, only Co clusters meet their stable state and undergo a transition. Atomistic simulations on a picosecond to nanosecond time scale evidence kinetic limitations for Pt and Pd, and allow us to understand the experimentally observed morphology for the different species. It is shown that stress relaxation, by strongly influencing the energy activation for atom hopping from first to second cluster layer and the magnitude of vibration of the atoms, is the determinant parameter for the existence or absence of the cluster morphology transition. DOI: 10.1103/PhysRevB.87.155404

Published
2013

48. Theory of Kerr effect in magnetic multilayered structures

Author

Fatiha Forati, Fabrice Scheurer, Alain Dereux, Christian Girard, and Jean-Pol Vigneron

Subjects
Electromagnetic field, Physics, Work (thermodynamics), Kerr effect, Field (physics), Discretization, Wave propagation, business.industry, Physics::Optics, Optical field, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Computational physics, Optics, business, Anisotropy, Instrumentation
Abstract

This work develops the theory of electromagnetic wave propagation through multilayered structures made of anisotropic materials. The proposed method of resolution is based on the Green's dyadic technique. The electromagnetic field scattered by the multilayer is obtained as the solution of a Lippmann-Schwinger equation that can be solved numerically for an arbitrary profile of the anisotropic dielectric tensor. The technique does not rely on any other approximation than the number of points used in the one-dimensional discretization grid so that thin as well as thick layers are tractable on the same footing. Applications to magneto-optical effects in various multilayered structures are discussed from the computed reflected field (Kerr effect).

Published
1995
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49. Robust spin crossover and memristance across a single molecule

Author

Eric Beaurepaire, Wulf Wulfhekel, Martin Bowen, Manuel Gruber, Loïc Joly, Fabrice Scheurer, Guillaume Rogez, V. Davesne, Toyo Kazu Yamada, Philippe Ohresser, T. Miyamachi, and Samy Boukari

Subjects
Multidisciplinary, Materials science, Condensed matter physics, Spin states, Basis (linear algebra), Aucun, General Physics and Astronomy, Molecular electronics, Nanotechnology, General Chemistry, General Biochemistry, Genetics and Molecular Biology, Spin crossover, Molecule, Condensed Matter::Strongly Correlated Electrons, Layer (electronics), Metallic substrate
Abstract

A nanoscale molecular switch can be used to store information in a single molecule. Although the switching process can be detected electrically in the form of a change in the molecule's conductance, adding spin functionality to molecular switches is a key concept for realizing molecular spintronic devices. Here we show that iron-based spin-crossover molecules can be individually and reproducibly switched between a combined high-spin, high-conduction state and a low-spin, low-conduction state, provided the individual molecule is decoupled from a metallic substrate by a thin insulating layer. These results represent a step to achieving combined spin and conduction switching functionality on the level of individual molecules.

Published
2012

50. Impact on Interface Spin Polarization of Molecular Bonding to Metallic Surfaces

Author

Yannick J. Dappe, Mebarek Alouani, Martin Bowen, J.-B. Beaufrand, Eric Beaurepaire, Wulf Wulfhekel, S. Javaid, Loïc Joly, Xi Chen, Samy Boukari, Jacek Arabski, Fabrice Scheurer, and J. P. Kappler

Subjects
Materials science, Spintronics, Spin polarization, Absorption spectroscopy, Exchange interaction, General Physics and Astronomy, chemistry.chemical_element, Manganese, Thermal conduction, Metal, chemistry, Chemical physics, visual_art, visual_art.visual_art_medium, Molecule, Atomic physics
Abstract

We have studied the repercussion of the molecular adsorption mechanism on the electronic properties of the interface between model nonmagnetic or magnetic metallic surfaces and metallo-organic phthalocyanines molecules (Pcs). Our intertwined x-ray absorption spectroscopy experiments and computational studies reveal that manganese Pc (MnPc) is physisorbed onto a Cu(001) surface and retains the electronic properties of a free molecule. On the other hand, MnPc is chemisorbed onto Co(001), leading to a dominant direct exchange interaction between the Mn molecular site and the Co substrate. By promoting an interfacial spin-polarized conduction state on the molecule, these interactions reveal an important lever to tailor the spintronic properties of hybrid organic-metallic interfaces.

Published
2010
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