Author: "Fabrice Scheurer" / Search Limiters: Available in Library Collection - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Fabrice Scheurer"' showing total 37 results

Start Over Author "Fabrice Scheurer" Search Limiters Available in Library Collection

37 results on '"Fabrice Scheurer"'

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
Full Text: View/download PDF

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
Full Text: View/download PDF

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
Full Text: View/download PDF

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
Full Text: View/download PDF

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
Full Text: View/download PDF

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
Full Text: View/download PDF

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
Full Text: View/download PDF

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
Full Text: View/download PDF

11. 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
Full Text: View/download PDF

12. 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
Full Text: View/download PDF

13. 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
Full Text: View/download PDF

14. 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
Full Text: View/download PDF

15. 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
Full Text: View/download PDF

16. 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
Full Text: View/download PDF

17. 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
Full Text: View/download PDF

18. 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
Full Text: View/download PDF

19. 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
Full Text: View/download PDF

20. 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
Full Text: View/download PDF

21. 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
Full Text: View/download PDF

22. 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
Full Text: View/download PDF

23. 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
Full Text: View/download PDF

24. 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
Full Text: View/download PDF

25. 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
Full Text: View/download PDF

26. 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
Full Text: View/download PDF

27. 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
Full Text: View/download PDF

28. 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
Full Text: View/download PDF

29. 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
Full Text: View/download PDF

30. 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
Full Text: View/download PDF

31. Magnetism and Synchrotron Radiation: Towards the Fourth Generation Light Sources

Author: Eric Beaurepaire, Hervé Bulou, Fabrice Scheurer, and Loïc Joly
Subjects: Physics, Optics, Magnetism, business.industry, Fourth generation, Synchrotron radiation, business
Published: 2013
Full Text: View/download PDF

32. 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

33. 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
Full Text: View/download PDF

34. Real-Time Monitoring of Growing Nanoparticles

Author: Yves Borensztein, O. Ulrich, Fabrice Scheurer, M. Noblet, Jeannot Mane-Mane, Antoine Barbier, Rémi Lazzari, Jacques Jupille, Gilles Renaud, Claude Henry, Frédéric Leroy, J.P. Deville, Olivier Fruchart, C. Revenant, Oxydes en basses dimensions (INSP-E9), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Service de Physique et de Chimie des Surfaces et Interfaces (SPCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Service de Physique des Matériaux et Microstructures (SP2M - UMR 9002), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Physico-chimie et dynamique des surfaces (INSP-E6), Service de Cytogénétique et de Biologie Cellulaire, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Hôpital Pontchaillou-CHU Pontchaillou [Rennes], 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), Laboratoire Louis Néel (LLN), Centre National de la Recherche Scientifique (CNRS), 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), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Hôpital Pontchaillou-CHU Pontchaillou [Rennes], 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: Multidisciplinary, business.industry, Scattering, Nanoparticle, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Optics, Macroscopic scale, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Optoelectronics, Particle, Process control, Sensitivity (control systems), Particle size, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Small-angle scattering, 0210 nano-technology, business, ComputingMilieux_MISCELLANEOUS
Abstract: One challenge in the production of nanometer-sized objects with given properties is to control their growth at a macroscopic scale in situ and in real time. A dedicated ultrahigh-vacuum grazing-incidence small-angle x-ray scattering setup has been developed, yielding high sensitivity and dynamics. Its capabilities to derive the average particle shape and size and the film growth mode and ordering and to probe both surfaces and buried interfaces are illustrated for two prototypical cases: the model catalyst Pd/MgO(100) and the self-organized Co/Au(111) system. A wide range of technologically important systems can potentially be investigated in various gaseous environments.
Published: 2003
Full Text: View/download PDF

35. Single-molecule tautomerization tracking through space- and time-resolved fluorescence spectroscopy

Author: Tomáš Neuman, Guillaume Schull, Michelangelo Romeo, Luis E. Parra López, Ruben Soria-Martinez, Benjamin Doppagne, Stéphane Berciaud, Javier Aizpurua, Fabrice Scheurer, Hervé Bulou, 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), Donostia International Physics Center (DIPC), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), schull, guillaume, European Research Council, European Commission, Agence Nationale de la Recherche (France), Université de Strasbourg, Ministerio de Economía y Competitividad (España), Eusko Jaurlaritza, 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: Molecular switch, [PHYS]Physics [physics], Materials science, Biomedical Engineering, Molecular electronics, Bioengineering, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Single-molecule experiment, 01 natural sciences, Tautomer, Atomic and Molecular Physics, and Optics, Fluorescence spectroscopy, Spectral line, 0104 chemical sciences, [PHYS] Physics [physics], Chemical physics, Excited state, Molecule, General Materials Science, Electrical and Electronic Engineering, 0210 nano-technology
Abstract: Tautomerization, the interconversion between two constitutional molecular isomers, is ubiquitous in nature, plays a major role in chemistry and is perceived as an ideal switch function for emerging molecular-scale devices. Within free-base porphyrin, porphycene or phthalocyanine, this process involves the concerted or sequential hopping of the two inner hydrogen atoms between equivalent nitrogen sites of the molecular cavity. Electronic and vibronic changes that result from this NH tautomerization, as well as details of the switching mechanism, were extensively studied with optical spectroscopies, even with single-molecule sensitivity. The influence of atomic-scale variations of the molecular environment and submolecular spatial resolution of the tautomerization could only be investigated using scanning probe microscopes, at the expense of detailed information provided by optical spectroscopies. Here, we combine these two approaches, scanning tunnelling microscopy (STM) and fluorescence spectroscopy, to study the tautomerization within individual free-base phthalocyanine (HPc) molecules deposited on a NaCl-covered Ag(111) single-crystal surface. STM-induced fluorescence (STM-F) spectra exhibit duplicate features that we assign to the emission of the two molecular tautomers. We support this interpretation by comparing hyper-resolved fluorescence maps(HRFMs) of the different spectral contributions with simulations that account for the interaction between molecular excitons and picocavity plasmons. We identify the orientation of the molecular optical dipoles, determine the vibronic fingerprint of the tautomers and probe the influence of minute changes in their atomic-scale environment. Time-correlated fluorescence measurements allow us to monitor the tautomerization events and to associate the proton dynamics to a switching two-level system. Finally, optical spectra acquired with the tip located at a nanometre-scale distance from the molecule show that the tautomerization reaction occurs even when the tunnelling current does not pass through the molecule. Together with other observations, this remote excitation indicates that the excited state of the molecule is involved in the tautomerization reaction path., The authors thank V. Speisser for technical support and A. Boeglin and Andrei Borissov for fruitful discussions. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 771850). The Agence National de la Recherche (project SMALL’LED no. ANR-14-CE26-0016-01), the Labex NIE (Contract no. ANR-11- LABX-0058_NIE) and the International Center for Frontier Research in Chemistry (FRC) are acknowledged for financial support. R.S.-M. and H.B. acknowledge GENCICINES (Project no. A0060907459) and the Pôle HPC and Equipex Equip@Meso at the University of Strasbourg. T.N. and J.A. acknowledge the project FIS2016-80174-P from the Spanish Ministry of Science, and project ELKARTEK KK-2018/00001 from the Basque Government, as well as grant IT1164-19 from the Basque Government for consolidated groups at the university
Full Text: View/download PDF

36. Energy funnelling within multichromophore architectures monitored with subnanometre resolution

Author: Michel Féron, Benjamin Doppagne, Fabrice Scheurer, Hervé Bulou, Anna Rosławska, Guillaume Schull, Shuiyan Cao, Michelangelo Romeo, Frédéric Chérioux, Nanjing University of Aeronautics and Astronautics (Nanjing University of Aeronautics and Astronautics), 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), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Femto-st, MN2S, 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 de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-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: Resonant inductive coupling, Light, General Chemical Engineering, [SPI.NANO] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, FOS: Physical sciences, Trimer, [SPI.MAT] Engineering Sciences [physics]/Materials, Isoindoles, 010402 general chemistry, 01 natural sciences, Fluorescence, [SPI.MAT]Engineering Sciences [physics]/Materials, Biomimetics, Microscopy, Scanning Tunneling, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Organometallic Compounds, Molecule, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Quantum tunnelling, ComputingMilieux_MISCELLANEOUS, Fluorescent Dyes, Physics, [PHYS]Physics [physics], [SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], [SPI.ACOU] Engineering Sciences [physics]/Acoustics [physics.class-ph], Condensed Matter - Mesoscale and Nanoscale Physics, 010405 organic chemistry, General Chemistry, Chromophore, Acceptor, 0104 chemical sciences, Energy Transfer, Chemical physics, Zinc Compounds, Luminescence, Energy (signal processing)
Abstract: In natural and artificial light-harvesting complexes (LHC) the resonant energy transfer (RET) between chromophores enables an efficient and directional transport of solar energy between collection and reaction centers. The detailed mechanisms involved in this energy funneling are intensely debated, essentially because they rely on a succession of individual RET steps that can hardly be addressed separately. Here, we developed a scanning tunnelling microscopy-induced luminescence (STML) approach allowing visualizing, addressing and manipulating energy funneling within multi-chromophoric structures with sub-molecular precision. We first rationalize the efficiency of the RET process at the level of chromophore dimers. We then use highly resolved fluorescence microscopy (HRFM) maps to follow energy transfer paths along an artificial trimer of descending excitonic energies which reveals a cascaded RET from high- to low-energy gap molecules. Mimicking strategies developed by photosynthetic systems, this experiment demonstrates that intermediate gap molecules can be used as efficient ancillary units to convey energy between distant donor and acceptor chromophores. Eventually, we demonstrate that the RET between donors and acceptors is enhanced by the insertion of passive molecules acting as non-covalent RET bridges. This mechanism, that occurs in experiments performed in inhomogeneous media and which plays a decisive role in fastening RET in photosynthetic systems, is reported at the level of individual chromophores with atomic-scale resolution. As it relies on organic chromophores as elementary components, our approach constitutes a powerful model to address fundamental physical processes at play in natural LHC.
Full Text: View/download PDF

37. Kondo screening of the spin and orbital magnetic moments of Fe impurities in Cu

Author: Christine Goyhenex, Fabrice Scheurer, J. P. Kappler, Loïc Joly, Pietro Gambardella, J.J. Kavich, Dong Jik Kim, Phillipe Sainctavit, Philippe Ohresser, F. Gautier, Yves Henry, Guy Schmerber, Hervé Bulou, Olivier M. Bengone, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), ICN2 - Institut Catala de Nanociencia i Nanotecnologia (ICN2), Universitat Autònoma de Barcelona (UAB), and Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)
Subjects: Physics, Condensed matter physics, Magnetic moment, Magnetic circular dichroism, Kondo effect, 02 engineering and technology, Atmospheric temperature range, 021001 nanoscience & nanotechnology, 01 natural sciences, Nuclear magnetic resonance, Impurity, 0103 physical sciences, Moment (physics), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Condensed Matter::Strongly Correlated Electrons, Absorption (chemistry), 010306 general physics, 0210 nano-technology, Spin (physics)
Abstract: We use x-ray magnetic circular dichroism to evidence the effect of correlations on the local impurity magnetic moment in an archetypal Kondo system, namely, a dilute Cu:Fe alloy. Applying the sum rules on the Fe ${L}_{2,3}$ absorption edges, the evolution of the spin and orbital moments across the Kondo temperature are determined separately. The spin moment presents a crossover from a nearly temperature-independent regime below the Kondo temperature to a paramagneticlike regime above. Conversely, the weak orbital moment shows a temperature-independent behavior in the whole temperature range, suggesting different Kondo screening temperature scales for the spin and orbital moments.
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Publication Type

Journal

Database

Publisher

37 results on '"Fabrice Scheurer"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources