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3. Unveiling the crystallization kinetics in Ge-rich Ge$_x$Te alloys by large scale simulations with a machine-learned interatomic potential

Author

Baratella, Dario, Kheir, Omar Abou El, and Bernasconi, Marco

Subjects
Condensed Matter - Materials Science, Condensed Matter - Disordered Systems and Neural Networks
Abstract

A machine-learned interatomic potential for Ge-rich Ge$_x$Te alloys has been developed aiming at uncovering the kinetics of phase separation and crystallization in these materials. The results are of interest for the operation of embedded phase change memories which exploits Ge-enrichment of GeSbTe alloys to raise the crystallization temperature. The potential is generated by fitting a large database of energies and forces computed within Density Functional Theory with the neural network scheme implemented in the DeePMD-kit package. The potential is highly accurate and suitable to describe the structural and dynamical properties of the liquid, amorphous and crystalline phases of the wide range of compositions from pure Ge and stoichiometric GeTe to the Ge-rich Ge$_2$Te alloy. Large scale molecular dynamics simulations revealed a crystallization mechanism which depends on temperature. At 600 K, segregation of most of Ge in excess occurs on the ns time scale followed by crystallization of nearly stoichiometric GeTe regions. At 500 K, nucleation of crystalline GeTe occurs before phase separation, followed by a slow crystal growth due to the concurrent expulsion of Ge in excess.

Published
2024

7. Unraveling the Crystallization Kinetics of the Ge$_2$Sb$_2$Te$_5$ Phase Change Compound with a Machine-Learned Interatomic Potential

Author

Kheir, Omar Abou El, Bonati, Luigi, Parrinello, Michele, and Bernasconi, Marco

Subjects
Condensed Matter - Materials Science, Condensed Matter - Disordered Systems and Neural Networks
Abstract

The phase change compound Ge$_2$Sb$_2$Te$_5$ (GST225) is exploited in advanced non-volatile electronic memories and in neuromorphic devices which both rely on a fast and reversible transition between the crystalline and amorphous phases induced by Joule heating. The crystallization kinetics of GST225 is a key functional feature for the operation of these devices. We report here on the development of a machine-learned interatomic potential for GST225 that allowed us to perform large scale molecular dynamics simulations (over 10000 atoms for over 100 ns) to uncover the details of the crystallization kinetics in a wide range of temperatures of interest for the programming of the devices. The potential is obtained by fitting with a deep neural network (NN) scheme a large quantum-mechanical database generated within Density Functional Theory. The availability of a highly efficient and yet highly accurate NN potential opens the possibility to simulate phase change materials at the length and time scales of the real devices.

Published
2023
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8. NJOY+NCrystal: an open-source tool for creating thermal neutron scattering libraries

Author

Ramic, Kemal, Damian, Jose Ignacio Marquez, Kittelmann, Thomas, Di Julio, Douglas D., Campi, Davide, Bernasconi, Marco, Gorini, Giuseppe, and Santoro, Valentina

Subjects
Physics - Instrumentation and Detectors, Condensed Matter - Materials Science
Abstract

In this work we present NJOY+NCrystal, a tool to generate thermal neutron scattering libraries with support for coherent and incoherent elastic components for crystalline solid materials. This tool, which is a customized version of NJOY, was created by modifying the nuclear data processing program NJOY to call the thermal scattering software library NCrystal, and includes a proposed change in the ENDF-6 format to store both the coherent and incoherent elastic components. Necessary changes to enable this format in NJOY, as well as to sample it in the OpenMC Monte Carlo code, are detailed here. Examples of materials that are coherent-dominant, incoherent-dominant, and mixed elastic scatterers are presented, as well as the creation of novel libraries for MgH$_2$ and MgD$_2$, that are under consideration as advanced neutron reflectors in the HighNESS project at the European Spallation Source. NJOY+NCrystal simplifies greatly the process to generate thermal scattering libraries (TSL) and this is exemplified with 213 new and updated TSL evaluations.

Published
2021
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11. THz Surface Modes and Electron-Phonon Coupling in Bi$_2$Se$_3$(111)

Author

Ruckhofer, Adrian, Campi, Davide, Bremholm, Martin, Hofmann, Philip, Bendek, Giorgio, Bernasconi, Marco, Ernst, Wolfgang E., and Tamtögl, Anton

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We present a combined experimental and theoretical study of the surface vibrational modes of the topological insulator (TI) Bi$_2$Se$_3$ with particular emphasis on the low-energy region below 10 meV that has been difficult to resolve experimentally. By applying inelastic helium atom scattering (HAS), the entire phonon dispersion was determined and compared with density functional perturbation theory (DFPT) calculations. The intensity of the phonon modes is dominated by a strong Rayleigh mode, in contrast to previous experimental works. Moreover, also at variance with recent reports, no Kohn-anomaly is observed. These observations are in excellent agreement with DFPT calculations. Besides these results, the experimental data reveal$-$via bound-state resonance enhancement$-$two additional dispersion curves in the gap below the Rayleigh mode. They are possibly associated with an excitation of a surface electron density superstructure that we observe in HAS diffraction patterns. The electron-phonon coupling paramenter $\lambda$ = 0.23 derived from our temperature dependent Debye-Waller measurements compares well with values determined by angular resolved photoemission or Landau level spectroscopy. Our work opens up a new perspective for THz measurements on 2D materials as well as the investigation of subtle details (band bending, the presence of quantum well states) with respect to the electron-phonon coupling.

Published
2019
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15. Die Kunstdenkmäler des Kantons Basel-Stadt X

Author

Meier, Hans-Rudolf, Schwinn Schürmann, Dorothea, Bernasconi, Marco, Hess, Stefan, Jäggi, Carola, Nagel, Anne, and Pajor, Ferdinand

Subjects
Architektur, Baukunst, standortgebundene Kunst, Städtebau, Architekturgeschichte, Regionalgeschichte, Kunstgeschichte, bic Book Industry Communication::A The arts::AM Architecture::AMX History of architecture
Abstract

projektrelevanten Institutionen – Evangelisch-reformierte Kirche Basel-Stadt, Basler Münsterbauhütte, Kantonale Denkmalpflege und Archäologische Bodenforschung Basel-Stadt sowie die Universität und als Vertreterin der interessierten Öffentlichkeit die Basler Ständerätin – eingebunden waren. Die Gesamtdarstellung basiert auf der Aufarbeitung bisheriger Forschungen, auf zahlreichen neu erschlossenen Schrift- und Bildquellen, neuesten restauratorischen und bauarchäologischen Befunden sowie auf dem Austausch mit zahlreichen am und mit dem Münster beschäftigten Fachspezialisten verschiedener Richtungen. Die akribische Analyse der Grabungsdokumentation ergab eine differenzierte und in manchen Punkten vom bisher Bekannten abweichende Darstellung der Vorgängerbauten. Das vorhandene Wissen wurde kritisch gesichtet und zusammengeführt und erbrachte mit dem beschreibenden Erfassen und Einordnen des Bestands neue Erkenntnisse zur Baugeschichte, Architektur und Bauskulptur. So konnte beispielsweise eine Chronologie des spätromanischen Baus erarbeitet werden, in der das vieldiskutierte Branddatum 1185 mit Befunden korreliert. Erstmals wird die gesamte vor- und nachreformatorische Ausstattung des Münsters – nicht nur die erhaltene, sondern auch die in Schrift- und Bildquellen überlieferte und verschwundene – zusammengestellt bzw. gewürdigt. Sowohl die heute weitgehend zerstörte malerische Ausschmückung wie auch die skulpturale Ausstattung und Möblierung des Kirchenraums erhielten systematische Zusammenschauen. Auch die in grosser Zahl erhaltenen Grabmäler wurden umfassend aufgelistet und in einer repräsentativen Auswahl vorgestellt. Ein historischer Überblick, Ausführungen zur Liturgie, zur vor- und nachreformatorischen „Bespielung“ und Nutzung des Münsters, aber auch nützliche, gehaltvolle Exkurse, wie beispielsweise zu den Rechnungsbüchern der Münsterbauhütte oder zum Baumaterial, gehen weit über das reine Inventarwerk hinaus. Der mehr als 500 Seiten umfassende Kunstdenkmälerband über das Basler Münster wird nicht nur der Forschung und den Fachleuten, der Denkmalpflege und der Münsterbauhütte, Architekten und Universitäten als Informationsquelle im Berufsalltag dienen, sondern auch Kunstfreunden, Fremdenführern und Touristen ein attraktives Nachschlagewerk sein. Dem Autorenteam ist es gelungen, das reiche und sehr komplexe Material in eine wissenschaftlich fundierte, aber gleichwohl übersichtliche und leserfreundliche Form zu bringen. Entstanden ist eine attraktive, mit vielen Neuaufnahmen reich bebilderte Gesamtdarstellung, die dem grössten und wichtigen Kirchenbau der Stadt Basel zur Millenniumsfeier die gebührende Ehre erweist.

Published
2019
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17. Crystallization kinetics of nanoconfined GeTe slabs in GeTe/TiTe2-like superlattices for phase change memories

Author

Acharya, D, Abou El Kheir, O, Campi, D, Bernasconi, M, Acharya, Debdipto, Abou El Kheir, Omar, Campi, Davide, Bernasconi, Marco, Acharya, D, Abou El Kheir, O, Campi, D, Bernasconi, M, Acharya, Debdipto, Abou El Kheir, Omar, Campi, Davide, and Bernasconi, Marco

Abstract

Superlattices made of alternating blocks of the phase change compound Sb2Te3 and of TiTe2 confining layers have been recently proposed for applications in neuromorphic devices. The Sb2Te3 /TiTe2 heterostructure allows for a better control of multiple intermediate resistance states and for a lower drift with time of the electrical resistance of the amorphous phase. However, Sb2Te3 suffers from a low data retention due to a low crystallization temperature T x . Substituting Sb2Te3 with a phase change compound with a higher T x , such as GeTe, seems an interesting option in this respect. Nanoconfinement might, however, alters the crystallization kinetics with respect to the bulk. In this work, we investigated the crystallization process of GeTe nanoconfined in geometries mimicking GeTe/TiTe2 superlattices by means of molecular dynamics simulations with a machine learning potential. The simulations reveal that nanoconfinement induces a mild reduction in the crystal growth velocities which would not hinder the application of GeTe/TiTe2 heterostructures in neuromorphic devices with superior data retention.

Published
2024

18. Atomistic simulations of GeSbTe alloys for applications in electronic phase change memories

Author

Baratella, D, BERNASCONI, MARCO, BARATELLA, DARIO, Baratella, D, BERNASCONI, MARCO, and BARATELLA, DARIO

Abstract

The scope of this thesis is the study of some properties of GeSbTe alloys by means of atomistic simulations. These alloys are classified as phase change materials which are employed in data storage applications, such as a novel type of electronic non-volatile memory called Phase Change Memory (PCM). The prototypical alloy used so far in PCM is the Ge2Sb2Te5 (GST225) compound. In recent times, PCM has also gained significant attention for embedded memories for automotive applications. However, the crystallization temperature Tx (420 K) of GST225 is too low for applications that require data retention at higher temperatures. Therefore, other options have been investigated for these applications. Ge-rich GeSbTe alloys have emerged as the most promising materials for embedded memories. The Tx of the Ge-rich GST alloy is higher compared to the stoichiometric alloy GST225, because of phase separation with segregation of Ge atoms during crystallization. However, atomistic details of the phase separation and crystallization processes of Ge-rich GeSbTe alloys are not fully understood. In this respect, atomistic simulations could provide details at the atomistic level of both the crystallization and segregation phenomena. On these premises, in this thesis we addressed by atomistic simulations three different issues on the properties of phase change materials of interest for applications in PCM. Firstly, we calculated the electrical and thermal conductivities and the Seebeck coefficient of the liquid phase of GST225 by molecular dynamics simulations based on density functional theory (DFT), since these coefficients are needed to perform an electrothermal modeling of the PCM. Secondly, we studied the effect of H/N doping on the atomic mobility in Ge5Sb2Te3 and Ge2Te by DFT molecular dynamics in the liquid e supercooled liquid phase. Indeed, in literature it was reported that presence of N could further raise the Tx of Ge-rich GeSbTe alloys probably due to the reduction of Ge mo, The scope of this thesis is the study of some properties of GeSbTe alloys by means of atomistic simulations. These alloys are classified as phase change materials which are employed in data storage applications, such as a novel type of electronic non-volatile memory called Phase Change Memory (PCM). The prototypical alloy used so far in PCM is the Ge2Sb2Te5 (GST225) compound. In recent times, PCM has also gained significant attention for embedded memories for automotive applications. However, the crystallization temperature Tx (420 K) of GST225 is too low for applications that require data retention at higher temperatures. Therefore, other options have been investigated for these applications. Ge-rich GeSbTe alloys have emerged as the most promising materials for embedded memories. The Tx of the Ge-rich GST alloy is higher compared to the stoichiometric alloy GST225, because of phase separation with segregation of Ge atoms during crystallization. However, atomistic details of the phase separation and crystallization processes of Ge-rich GeSbTe alloys are not fully understood. In this respect, atomistic simulations could provide details at the atomistic level of both the crystallization and segregation phenomena. On these premises, in this thesis we addressed by atomistic simulations three different issues on the properties of phase change materials of interest for applications in PCM. Firstly, we calculated the electrical and thermal conductivities and the Seebeck coefficient of the liquid phase of GST225 by molecular dynamics simulations based on density functional theory (DFT), since these coefficients are needed to perform an electrothermal modeling of the PCM. Secondly, we studied the effect of H/N doping on the atomic mobility in Ge5Sb2Te3 and Ge2Te by DFT molecular dynamics in the liquid e supercooled liquid phase. Indeed, in literature it was reported that presence of N could further raise the Tx of Ge-rich GeSbTe alloys probably due to the reduction of Ge mo

Published
2024

20. Inverse simulated annealing: Improvements and application to amorphous InSb

Author

Los, Jan H., Gabardi, Silvia, Bernasconi, Marco, and Kühne, Thomas D.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Disordered Systems and Neural Networks, Physics - Computational Physics
Abstract

An improved inverse simulated annealing method is presented to determine the structure of complex disordered systems from first principles in agreement with available experimental data or desired predetermined target properties. The effectiveness of this method is demonstrated by revisiting the structure of amorphous InSb. The resulting network is mostly tetrahedral and in excellent agreement with available experimental data., Comment: 9 pages, 7 figure

Published
2014

21. Theoretical calculations of neutron scattering cross sections for tetrahydrofuran-containing clathrate hydrates at low temperature

Author

Xu Shuqi, Laporte Sara Isaline, DiJulio Douglas D., Marquez Damian Jose Ignacio, Kittelmann Thomas, Bernasconi Marco, Campi Davide, Gorini Giuseppe, and Santoro Valentina

Subjects
Physics, QC1-999
Abstract

Tetrahydrofuran-containing clathrate hydrate is considered as a potential cold and very cold neutron moderator material. The fully deuterated form is more promising because of the lower neutron absorption cross section of deuterium. In this work we present theoretical calculations of neutron scattering cross sections for hydrogenated and deuterated clathrates at low temperature. The scattering cross sections are generated by using the crystalline structure and phonon density of states obtained from density functional theory calculations. The theoretical neutron scattering cross sections serve to compare against existing or future experimental data.

Published
2023
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22. Electron-phonon interaction and thermal boundary resistance at the crystal-amorphous interface of the phase change compound GeTe

Author

Campi, Davide, Donadio, Davide, Sosso, Gabriele C, Behler, Jörg, and Bernasconi, Marco

Subjects
Mathematical Sciences, Physical Sciences, Engineering, Applied Physics
Abstract

Phonon dispersion relations and electron-phonon coupling of hole-doped trigonal GeTe have been computed by density functional perturbation theory. This compound is a prototypical phase change material of interest for applications in phase change non-volatile memories. The calculations allowed us to estimate the electron-phonon contribution to the thermal boundary resistance at the interface between the crystalline and amorphous phases present in the device. The lattice contribution to the thermal boundary resistance has been computed by non-equilibrium molecular dynamics simulations with an interatomic potential based on a neural network scheme. We find that the electron-phonon term contributes to the thermal boundary resistance to an extent which is strongly dependent on the concentration and mobility of the holes. Further, for measured values of the holes concentration and electrical conductivity, the electron-phonon term is larger than the contribution from the lattice. It is also shown that the presence of Ge vacancies, responsible for the p-type degenerate character of the semiconductor, strongly affects the lattice thermal conductivity of the crystal.

Published
2015

24. Breakdown of Stokes-Einstein relation in the supercooled liquid state of phase change materials

Author

Sosso, Gabriele C., Behler, Joerg, and Bernasconi, Marco

Subjects
Condensed Matter - Disordered Systems and Neural Networks
Abstract

The application of amorphous chalcogenide alloys as data-storage media relies on their ability to undergo an extremely fast (10-100 ns) crystallisation once heated at sufficiently high temperature. However, the peculiar features that make these materials so attractive for memory devices still lack a comprehensive microscopic understanding. By means of large scale molecular dynamics simulations, we demonstrate that the supercooled liquid of the prototypical compound GeTe shows a very high atomic mobility (D \sim 10^(-6) cm2/s) down to temperatures close to the glass transition temperatures. This behaviour leads to a breakdown of the Stokes-Einstein relation between the self- diffusion coefficient and the viscosity in the supercooled liquid. The results suggest that the fragility of the supercooled liquid is the key to understand the fast crystallisation process in this class of materials., Comment: 6 pages, 4 figures

Published
2012
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25. A neural network interatomic potential for the phase change material GeTe

Author

Sosso, Gabriele C., Miceli, Giacomo, Caravati, Sebastiano, Behler, Jörg, and Bernasconi, Marco

Subjects
Condensed Matter - Materials Science, Condensed Matter - Disordered Systems and Neural Networks
Abstract

GeTe is a prototypical phase change material of high interest for applications in optical and electronic non-volatile memories. We present an interatomic potential for the bulk phases of GeTe, which is created using a neural network (NN) representation of the potential-energy surface obtained from reference calculations based on density functional theory. It is demonstrated that the NN potential provides a close to ab initio quality description of a number of properties of liquid, crystalline and amorphous GeTe. The availability of a reliable classical potential allows addressing a number of issues of interest for the technological applications of phase change materials, which are presently beyond the capability of first principles molecular dynamics simulations., Comment: 12 pages, 17 figures

Published
2012
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26. Nuclear quantum effects in ab initio dynamics: theory and experiments for lithium imide

Author

Ceriotti, Michele, Miceli, Giacomo, Pietropaolo, Antonino, Colognesi, Daniele, Nale, Angeloclaudio, Catti, Michele, Bernasconi, Marco, and Parrinello, Michele

Subjects
Condensed Matter - Materials Science, Physics - Computational Physics
Abstract

Owing to their small mass, hydrogen atoms exhibit strong quantum behavior even at room temperature. Including these effects in first principles calculations is challenging, because of the huge computational effort required by conventional techniques. Here we present the first ab-initio application of a recently-developed stochastic scheme, which allows to approximate nuclear quantum effects inexpensively. The proton momentum distribution of lithium imide, a material of interest for hydrogen storage, was experimentally measured by inelastic neutron scattering experiments and compared with the outcome of quantum thermostatted ab initio dynamics. We obtain favorable agreement between theory and experiments for this purely quantum mechanical property, thereby demonstrating that it is possible to improve the modelling of complex hydrogen-containing materials without additional computational effort.

Published
2010
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27. Static disorder and structural correlations in the low temperature phase of lithium imide

Author

Miceli, Giacomo, Ceriotti, Michele, Bernasconi, Marco, and Parrinello, Michele

Subjects
Condensed Matter - Materials Science
Abstract

Based on ab-initio molecular dynamics simulations, we investigate the low temperature crystal structure of Li2NH which in spite of its great interest as H-storage material is still matter of debate. The dynamical simulations reveal a precise correlation in the fractional occupation of Li sites which leads average atomic positions in excellent agreement with diffraction data and solves inconsistencies of previous proposals.

Published
2010
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29. Fundchronik: Ausgrabungen und Funde im Jahr 2022

Author

Allemann, Martin, primary, Bernasconi, Marco, additional, Billo, Sven, additional, Braun, Ingmar M., additional, Graber, Simon, additional, Hodel, Corinne, additional, Ketzler, Michael, additional, Lenz, Lara, additional, Martin, Erik, additional, Savary, Johann, additional, Schmidig, Roman, additional, Steiner, Susan, additional, Wimmer, Johannes, additional, Wyss, Benedikt, additional, Blättler, Hubert, additional, and Glaser, Viviane, additional

Published
2023
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30. Thick Does the Trick: Genesis of Ferroelectricity in 2D GeTe‐Rich (GeTe)m(Sb2Te3)n Lamellae

Author

Cecchi, Stefano, primary, Momand, Jamo, additional, Dragoni, Daniele, additional, Abou El Kheir, Omar, additional, Fagiani, Federico, additional, Kriegner, Dominik, additional, Rinaldi, Christian, additional, Arciprete, Fabrizio, additional, Holý, Vaclav, additional, Kooi, Bart J., additional, Bernasconi, Marco, additional, and Calarco, Raffaella, additional

Published
2023
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31. Diffusion and desorption of SiH3 on hydrogenated H:Si(100)-(2x1) from first principles

Author

Ceriotti, Michele and Bernasconi, Marco

Subjects
Condensed Matter - Materials Science
Abstract

We have studied diffusion pathways of a silyl radical adsorbed on the hydrogenated Si (100)-(2x1) surface by density-functional theory. The process is of interest for the growth of crystalline silicon by plasma-enhanced chemical vapor deposition. Preliminary searches for migration mechanisms have been performed using metadynamics simulations. Local minima and transition states have been further refined by using the nudged-elastic-band method. Barriers for diffusion from plausible adsorption sites as low as 0.2 eV have been found, but trap states have also been spotted, leading to a more stable configuration, with escape barriers of 0.7 eV. Diffusion among weakly bound physisorbed states is also possible with very low activation barriers (<50 meV). However, desorption mechanisms (either as SiH3 or as SiH4) from physisorbed or more strongly bound adsorption configurations turn out to have activation energies similar to diffusion barriers. Kinetic Monte Carlo simulations based on ab initio activation energies show that the silyl radical diffuses at most by a few lattice spacing before desorbing at temperatures in the range 300-1000 K.

Published
2008
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32. Ab initio study of the vibrational properties of crystalline TeO2: The alpha, beta, and gamma phases

Author

Ceriotti, Michele, Pietrucci, Fabio, and Bernasconi, Marco

Subjects
Condensed Matter - Materials Science
Abstract

Based on density functional perturbation theory, we have studied the vibrational properties of three crystalline phases of tellurium dioxide: paratellurite alpha-TeO2, tellurite beta-TeO2, and the new phase gamma-TeO2, recently identified experimentally. Calculated Raman and IR spectra are in good agreement with available experimental data. The vibrational spectra of alpha- and beta-TeO2 can be interpreted in terms of vibrations of TeO2 molecular units.

Published
2008
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33. Functional Properties of Phase Change Materials from Atomistic Simulations

Author

Caravati, Sebastiano, Sosso, Gabriele C., Bernasconi, Marco, Hull, Robert, Series editor, Jagadish, Chennupati, Series editor, Osgood, Richard M., Series editor, Parisi, Jürgen, Series editor, Seong, Tae-Yeon, Series editor, Uchida, Shin-ichi, Series editor, Wang, Zhiming M., Series editor, Massobrio, Carlo, editor, Du, Jincheng, editor, Bernasconi, Marco, editor, and Salmon, Philip S., editor

Published
2015
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34. Unraveling the crystallization kinetics of the Ge2Sb2Te5 phase change compound with a machine-learned interatomic potential.

Author

Abou El Kheir, Omar, Bonati, Luigi, Parrinello, Michele, and Bernasconi, Marco

Subjects
CRYSTALLIZATION kinetics, ARTIFICIAL neural networks, REVERSIBLE phase transitions, PHASE transitions, PHASE change materials, MOLECULAR dynamics
Abstract

The phase change compound Ge2Sb2Te5 (GST225) is exploited in advanced non-volatile electronic memories and in neuromorphic devices which both rely on a fast and reversible transition between the crystalline and amorphous phases induced by Joule heating. The crystallization kinetics of GST225 is a key functional feature for the operation of these devices. We report here on the development of a machine-learned interatomic potential for GST225 that allowed us to perform large scale molecular dynamics simulations (over 10,000 atoms for over 100 ns) to uncover the details of the crystallization kinetics in a wide range of temperatures of interest for the programming of the devices. The potential is obtained by fitting with a deep neural network (NN) scheme a large quantum-mechanical database generated within density functional theory. The availability of a highly efficient and yet highly accurate NN potential opens the possibility to simulate phase change materials at the length and time scales of the real devices. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Thick Does the Trick: Genesis of Ferroelectricity in 2D GeTe‐Rich (GeTe)m(Sb2Te3)n Lamellae.

Author

Cecchi, Stefano, Momand, Jamo, Dragoni, Daniele, Abou El Kheir, Omar, Fagiani, Federico, Kriegner, Dominik, Rinaldi, Christian, Arciprete, Fabrizio, Holý, Vaclav, Kooi, Bart J., Bernasconi, Marco, and Calarco, Raffaella

Subjects
FERROELECTRICITY, FERROELECTRIC materials, PIEZORESPONSE force microscopy, DENSITY functional theory, PHASE change materials, MOLECULAR beam epitaxy
Abstract

The possibility to engineer (GeTe)m(Sb2Te3)n phase‐change materials to co‐host ferroelectricity is extremely attractive. The combination of these functionalities holds great technological impact, potentially enabling the design of novel multifunctional devices. Here an experimental and theoretical study of epitaxial (GeTe)m(Sb2Te3)n with GeTe‐rich composition is presented. These layered films feature a tunable distribution of (GeTe)m(Sb2Te3)1 blocks of different sizes. Breakthrough evidence of ferroelectric displacement in thick (GeTe)m(Sb2Te3)1 lamellae is provided. The density functional theory calculations suggest the formation of a tilted (GeTe)m slab sandwiched in GeTe‐rich blocks. That is, the net ferroelectric polarization is confined almost in‐plane, representing an unprecedented case between 2D and bulk ferroelectric materials. The ferroelectric behavior is confirmed by piezoresponse force microscopy and electroresistive measurements. The resilience of the quasi van der Waals character of the films, regardless of their composition, is also demonstrated. Hence, the material developed hereby gathers in a unique 2D platform the phase‐change and ferroelectric switching properties, paving the way for the conception of innovative device architectures. [ABSTRACT FROM AUTHOR]

Published
2024
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38. Thermal scattering libraries for cold and very-cold neutron reflector materials

Author

DiJulio, Douglas D., Damian, Jose Ignacio Marquez, Bernasconi, Marco, Campi, Davide, Gorini, Giuseppe, Kittelmann, Thomas, Klinkby, Esben, Muhrer, Gunter, Ramic, Kemal, Rizzi, Nicola, Santoro, Valentina, DiJulio, Douglas D., Damian, Jose Ignacio Marquez, Bernasconi, Marco, Campi, Davide, Gorini, Giuseppe, Kittelmann, Thomas, Klinkby, Esben, Muhrer, Gunter, Ramic, Kemal, Rizzi, Nicola, and Santoro, Valentina

Abstract

We present recent developments of improved modelling methods for simulating neutron transport in reflector materials of interest for neutron source applications. These include materials to be used as traditional reflectors around the neutron moderator, such as beryllium, and also novel materials, such as nanodiamond particles, to be used as a reflector for very-cold neutrons in the neutron beam extraction area of a neutron scattering instrument. Of particular interest is the inclusion of physical effects that are not modelled in standard thermal scattering libraries used for Monte-Carlo simulations, such as extinction in beryllium reflectors and effects of small-angle neutron scattering from nanodiamond particles.

Published
2023

39. Thermal scattering libraries for cold and very-cold neutron reflector materials

Author

Dijulio, D, Marquez Damian, J, Bernasconi, M, Campi, D, Gorini, G, Kittelmann, T, Klinkby, E, Muhrer, G, Ramic, K, Rizzi, N, Santoro, V, Dijulio, Douglas D., Marquez Damian, Jose Ignacio, Bernasconi, Marco, Campi, Davide, Gorini, Giuseppe, Kittelmann, Thomas, Klinkby, Esben, Muhrer, Gunter, Ramic, Kemal, Rizzi, Nicola, Santoro, Valentina, Dijulio, D, Marquez Damian, J, Bernasconi, M, Campi, D, Gorini, G, Kittelmann, T, Klinkby, E, Muhrer, G, Ramic, K, Rizzi, N, Santoro, V, Dijulio, Douglas D., Marquez Damian, Jose Ignacio, Bernasconi, Marco, Campi, Davide, Gorini, Giuseppe, Kittelmann, Thomas, Klinkby, Esben, Muhrer, Gunter, Ramic, Kemal, Rizzi, Nicola, and Santoro, Valentina

Abstract

We present recent developments of improved modelling methods for simulating neutron transport in reflector materials of interest for neutron source applications. These include materials to be used as traditional reflectors around the neutron moderator, such as beryllium, and also novel materials, such as nanodiamond particles, to be used as a reflector for very-cold neutrons in the neutron beam extraction area of a neutron scattering instrument. Of particular interest is the inclusion of physical effects that are not modelled in standard thermal scattering libraries used for Monte-Carlo simulations, such as extinction in beryllium reflectors and effects of small-angle neutron scattering from nanodiamond particles.

Published
2023

40. Atomistic simulations of Ge-rich GeSbTe alloys for phase change memories

Author

ABOU EL KHEIR, O, BERNASCONI, MARCO, ABOU EL KHEIR, OMAR, ABOU EL KHEIR, O, BERNASCONI, MARCO, and ABOU EL KHEIR, OMAR

Abstract

Prototypical phase change compounds, typically based on GeSbTe (GST) alloys, display a crystallization temperature not suitable for embedded Phase Change Memories (ePCM) of interest for applications in the automotive sector. The search for an alternative material is thus a very active research field. Ge-rich GST alloys are emerging as promising materials for ePCM thanks to the higher thermal stability of their amorphous phase. Upon crystallization, Ge-rich GST alloys undergo a phase separation into Ge and other GST alloys. The segregation phenomena enhance the crystallization temperature (Tx), but it comes also with several drawbacks such as a high cell-to-cell variability and a drift of the electrical resistance with time in the set state. The details regarding the decomposition process are largely unknown and are a matter of debate. During my PhD studies, I investigated the phase separation by means of high-throughput Density Functional theory (DFT) calculations based on thermodynamical analysis. We computed the formation free energy of all GST alloys in the central part of the ternary phase diagram modelled in the rocksalt metastable phase, which is the phase relevant to the operation of the memory. Then, we computed all possible decomposition reactions for each GST alloy. We summarized all our thermochemical data in one descriptor called "decomposition propensity", which measures the tendency of an alloy to undergo phase separation. I also studied the structural properties of the amorphous phase of Ge-rich GST alloys as a function of the Ge content. We found that by increasing the Ge content the local structure of the amorphous phase becomes more and more dissimilar from the crystalline phase which might hinder the crystallization kinetic. These results suggest a possible strategy to minimize the phase separation (low decomposition propensity) and still keep high Tx (crystallization might be hindered due to the dissimilarity). Aside the thermodynamic analysis di, Prototypical phase change compounds, typically based on GeSbTe (GST) alloys, display a crystallization temperature not suitable for embedded Phase Change Memories (ePCM) of interest for applications in the automotive sector. The search for an alternative material is thus a very active research field. Ge-rich GST alloys are emerging as promising materials for ePCM thanks to the higher thermal stability of their amorphous phase. Upon crystallization, Ge-rich GST alloys undergo a phase separation into Ge and other GST alloys. The segregation phenomena enhance the crystallization temperature (Tx), but it comes also with several drawbacks such as a high cell-to-cell variability and a drift of the electrical resistance with time in the set state. The details regarding the decomposition process are largely unknown and are a matter of debate. During my PhD studies, I investigated the phase separation by means of high-throughput Density Functional theory (DFT) calculations based on thermodynamical analysis. We computed the formation free energy of all GST alloys in the central part of the ternary phase diagram modelled in the rocksalt metastable phase, which is the phase relevant to the operation of the memory. Then, we computed all possible decomposition reactions for each GST alloy. We summarized all our thermochemical data in one descriptor called "decomposition propensity", which measures the tendency of an alloy to undergo phase separation. I also studied the structural properties of the amorphous phase of Ge-rich GST alloys as a function of the Ge content. We found that by increasing the Ge content the local structure of the amorphous phase becomes more and more dissimilar from the crystalline phase which might hinder the crystallization kinetic. These results suggest a possible strategy to minimize the phase separation (low decomposition propensity) and still keep high Tx (crystallization might be hindered due to the dissimilarity). Aside the thermodynamic analysis di

Published
2023

41. Omalus (Omalus) puncticeps Linsenmaier 1994

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Arthropoda, Omalus, Animalia, Biodiversity, Hymenoptera, Omalus puncticeps, Taxonomy
Abstract

Omalus (Omalus) puncticeps Linsenmaier, 1994 (Fig. 7A–7D) Omalus (Omalus) puncticeps Linsenmaier, 1994: 151 (descr.). Philoctetes puncticeps: Strumia 2008: 376. Type locality. United Arab Emirates: “ Holotype: &female;, U.A.E.: Shweib / Madam, 24.III.1987, Hamer, BMNH. Paratypes: 1&female;, Shweib, 1.IV.1987; 1&female;, Remah, 2.IV.1987; 1&female;, Abu Dhabi, 6.II.1987; 1&female;, Dubai Hatha, 22.II.1990; all Hamer, WLC; 1♁, Liwa, 23.III.1990, WLC; ♁ allotype, same data, BMNH”. Paratypes, 1♁: UAE Liwa 23.III.1990 I.L. Hamer // ♁ Paratype Omalus Pz. puncticeps Lins. Linsenmaier det. 1992 (ex synoptic-collection) // NML_ENT GBIF_Chr0001373; 1&female;: UAE Abu Dhabi (M) 6.II.87 I.L. Hamer // &female; Paratype Omalus Pz. puncticeps Lins. Linsenmaier det. 1989 (ex synoptic-collection) // NML_ENT GBIF_ Chr0001372; 1&female;: UAE Dubai / Hatta 22.2.1990 I.L. Hamer // &female; Paratype Omalus Pz. puncticeps Lins. Linsenmaier det. 1992 // NML_ENT GBIF_Chr0001374. Remarks. Strumia & Dawah (2010) transferred Omalus puncticeps to Philoctetes (sensu Kimsey & Bohart 1991) and recorded it from Saudi Arabia., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on page 69, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Linsenmaier, W. (1994) The Chrysididae (Insecta: Hymenoptera) of the Arabian Peninsula. Fauna of Saudi Arabia, 14, 145 - 206.","Strumia, F. (2008) Order Hymenoptera, family Chrysididae. Arthropod Fauna of the UAE, 1, 375 - 387.","Strumia, F. & Dawah, H. (2010 [\" 2008 - 2009 \"]) Contribution to the knowledge of Chrysididae of Saudi Arabia (Hymenoptera, Aculeata). Frustula Entomologica, New Series, 31 (44), 1 - 10.","Kimsey, L. S. & Bohart, R. M. (1991 [\" 1990 \"]) The Chrysidid Wasps of the World. Oxford University Press, New York, 664 pp."]}

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2023
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42. Omalus (Philoctetes) jemenensis Linsenmaier 1994

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Arthropoda, Omalus, Animalia, Biodiversity, Hymenoptera, Taxonomy, Omalus jemenensis
Abstract

Omalus (Philoctetes) jemenensis Linsenmaier, 1994 (Fig. 12 A–12D) Omalus (Philoctetes) jemenensis Linsenmaier, 1994: 151 (key, descr.), 152 (figs 3, 4). Philoctetes jemenensis: Strumia 2014: 472. Type locality. Yemen: “ Holotype: ♁, Yemen: Wadi Siham, 7.VI.1987, Mühle, WLC”. Holotype, ♁: N Jemen Wadi Siham 7.VI.1987 leg. Mühle // ♁ Type Omalus Pz. Philoctetes jemenensis Lins. Linsenmaier det. 1989 (ex type-collection) // NML_ENT GBIF_Chr0001694. Remarks. Strumia (2014) transferred this species to Philoctetes and recorded it from the United Arab Emirates., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on page 74, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Linsenmaier, W. (1994) The Chrysididae (Insecta: Hymenoptera) of the Arabian Peninsula. Fauna of Saudi Arabia, 14, 145 - 206.","Strumia, F. (2014) Order Hymenoptera, family Chrysididae Upgraded checklist of the Chrysididae from the UAE. Arthropod Fauna of the UAE, 5, 471 - 504."]}

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2023
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43. Holophris Mocsary 1890

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Arthropoda, Animalia, Biodiversity, Holophris, Hymenoptera, Taxonomy
Abstract

Subgenus Holophris Mocsáry, 1890 Remarks. Linsenmaier (1959a) did not include any Palaearctic species, but simply reported “Spezies in Nord- und Süd-Amerika, Afrika, Indonesien und Australien ”., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on page 78, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Mocsary, A. (1890) Additamentum primum ad monographiam Chrysididarum orbis terrarum universi. Termeszetrajzi Fuzetek, 13 (2 - 3), 45 - 66.","Linsenmaier, W. (1959 a) Revision der Familie Chrysididae (Hymenoptera) mit besonderer Berucksichtigung der europaischen Spezies. Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 32 (1), 1 - 232."]}

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2023
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44. Omalus (Omalus) pusillus subsp. semicupreus Lins. Linsenmaier 1959

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Arthropoda, Omalus, Omalus (omalus) pusillus semicupreus linsenmaier, 1959b, Animalia, Omalus pusillus, Biodiversity, Hymenoptera, Taxonomy
Abstract

Omalus (Omalus) pusillus semicupreus Linsenmaier, 1959b (Fig. 9A–9F) Omalus (Omalus) pusillus semicupreus Linsenmaier, 1959b: 233 (descr.). Pseudomalus pusillus semicupreus: Kimsey & Bohart 1991: 269 (cat.). Type locality. Spain: “Spanien (Alicante, Aranjuez), ♁ Type (Alicante) und Paratype Coll. m.”. Holotype, ♁ and Paratypes, 5♁: Spanien Alicante 15.–16.V.59 leg. Linsenmaier // ♁ Type u. Paratypen Omalus pusillus semicupreus Lins. Linsenmaier det. 1959 (ex type-collection) // NML_ENT GBIF_Chr0001553. Paratypes, 2♁: Spanien Aranjuez 25.V.59 leg. Linsenmaier // Paratypen Omalus pusillus semicupreus Lins. det. Linsenmaier 1959 (ex synoptic-collection) // NML_ENT GBIF_Chr0001543., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on page 72, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Linsenmaier, W. (1959 b) Revision der Familie Chrysididae (Hymenoptera). Nachtrag. Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 32 (2 - 3), 233 - 240.","Kimsey, L. S. & Bohart, R. M. (1991 [\" 1990 \"]) The Chrysidid Wasps of the World. Oxford University Press, New York, 664 pp.","Linsenmaier, W. (1959 a) Revision der Familie Chrysididae (Hymenoptera) mit besonderer Berucksichtigung der europaischen Spezies. Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 32 (1), 1 - 232."]}

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2023
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45. Omalus (Chrysellampus) nigromaculatus Linsenmaier 1997

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Arthropoda, Omalus, Omalus nigromaculatus, Animalia, Biodiversity, Hymenoptera, Taxonomy
Abstract

Omalus (Chrysellampus) nigromaculatus Linsenmaier, 1997 (Fig. 1A–1D) Omalus (Chrysellampus) nigromaculatus Linsenmaier, 1997: 249 (descr.), 295 (figs 194–197). Omalus (Philoctetes) pici (du Buysson, 1900): Arens 2014: 570 (synonymised). Type locality. Turkey: " Turkey, ♁ (Holotypus) Ankara, VII.62, Seidenstücker, Coll. m.". Holotype, ♁: Türkei Ankara VII.62 leg. Seidenstücker Coll. Linsenmaier // ♁ Type Omalus Pz. Chrysellampus nigromaculatus Lins. Linsenmaier det. 1995 (ex type-collection) // NML_ENT GBIF_Chr0001767. Remarks. Omalus (Chrysellampus) nigromaculatus was synonymised with O. pici (du Buysson) [currently Chrysellampus, described from Smyrne (= Ýzmir)] by Arens (2014). The species is known from East Mediterranean countries: Greece, Rhodos Is., and Turkey (Arens 2014). Linsenmaier (1959a) keyed and described Omalus (Chrysellampus) pici, but the latter was apparently overlooked by Linsenmaier (1997)., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on page 64, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Linsenmaier, W. (1997) Altes und Neues von den Chrysididen. (Hymenoptera, Chrysididae). Entomofauna, 18 (19), 245 - 300.","du Buysson, R. (1900) Contribution aux Chrysidides du Globe (4 e Serie). Revue d'Entomologie, 19, 125 - 160 + 2 pls.","Arens, W. (2014) Die Goldwespen der Peloponnes (Hymenoptera: Chrysididae) 1. Teil: Die Gattungen Cleptes, Omalus, Holopyga, Hedychrum, Hedychridium und Euchroeus; mit Beschreibung einer neuen Cleptes - Art. Linzer Biologische Beitrage, 46 (1), 553 - 621.","Linsenmaier, W. (1959 a) Revision der Familie Chrysididae (Hymenoptera) mit besonderer Berucksichtigung der europaischen Spezies. Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 32 (1), 1 - 232."]}

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2023
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46. Omalus (Omalus) viridiminor Lins. Linsenmaier 1999

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Arthropoda, Omalus, Omalus viridiminor, Animalia, Biodiversity, Hymenoptera, Taxonomy
Abstract

Omalus (Omalus) viridiminor Linsenmaier, 1999 (Fig. 11A–11D) Omalus (Omalus) viridiminor Linsenmaier, 1999: 14 (key), 19 (descr.), 23 (figs. 12, 13) Type locality. Tunisia: “Tunesien, Nefta IV.1927, &female; Type (Holotypus), &female; Paratype Coll. m.”. Holotype, &female;: Tunisien Nefta 4.[19]27 // &female; Type Omalus Pz. viridiminor Lins. Linsenmaier det. 1997 (ex type-collection) // NML_ENT GBIF_Chr0001556. Paratype, &female;: Tunisien Nefta 4.[19]27 // &female; Paratype Omalus Pz. viridiminor Lins. Linsenmaier det. 1997 // NML_ENT GBIF_Chr0001555. Remarks. Following Kimsey & Bohart (1991) classification, this taxon belongs to Philoctetes., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on page 73, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Linsenmaier, W. (1999) Die Goldwespen Nordafrikas (Hymenoptera, Chrysididae). Entomofauna, Supplement 10, 1 - 210.","Kimsey, L. S. & Bohart, R. M. (1991 [\" 1990 \"]) The Chrysidid Wasps of the World. Oxford University Press, New York, 664 pp."]}

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2023
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47. Omalus (Elampus) rufirostris Linsenmaier 1999

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Omalus rufirostris, Arthropoda, Omalus, Animalia, Biodiversity, Hymenoptera, Taxonomy
Abstract

Omalus (Elampus) rufirostris Linsenmaier, 1999 (Fig. 2A–2D) Omalus (Elampus) rufirostris Linsenmaier, 1999: 15 (key), 25 (figs 25-29), 26 (descr.). Elampus rufirostris: Strumia 2008: 376. Type locality. Morocco, Palestine: "Marokko, &female; Type (Holotypus) Agadir 2.V.1965 (im lockeren Gras einer Binnendüne), leg. und Coll. m.; &female; Paratype Val. Draa 28.V.1995, leg. und. Coll. Schmid-Egger. - Palästina, &female; Paratype N. Elat, Iddam 8.V.1996, leg. Irwin, Coll. Niehuis ". Holotype, &female;: Maroc, Agadir, 2.V.65, leg. Linsenmaier // Omalus Pz. Elampus rufirostris Lins. Linsenmaier det. 1997 (ex type-collection) // NML_ENT GBIF_Chr0001958. Remarks. Strumia (2008) reported this species from United Arab Emirates. Rosa et al. (2020a) considered this identification as doubtful, based on the picture of the Arabian specimen provided by Strumia (2008, plate 4)., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on pages 64-65, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Linsenmaier, W. (1999) Die Goldwespen Nordafrikas (Hymenoptera, Chrysididae). Entomofauna, Supplement 10, 1 - 210.","Strumia, F. (2008) Order Hymenoptera, family Chrysididae. Arthropod Fauna of the UAE, 1, 375 - 387.","Rosa, P., Gadallah, N. S. & Brothers, D. J. (2020 a) Biodiversity of the aculeate wasps (Hymenoptera: Aculeata) of the Arabian Peninsula: Chrysidoidea, Chrysididae. Zootaxa, 4754 (1), 92 - 101. https: // doi. org / 10.11646 / zootaxa. 4754.1.10"]}

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2023
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48. Omalus (Omalus) pusillus subsp. bulgariensis Linsenmaier 1959

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Arthropoda, Omalus, Animalia, Omalus pusillus, Omalus (omalus) pusillus bulgariensis linsenmaier, 1959a, Biodiversity, Hymenoptera, Taxonomy
Abstract

Omalus (Omalus) pusillus bulgariensis Linsenmaier, 1959a Omalus (Omalus) pusillus bulgariensis Linsenmaier, 1959a: 19 (descr.). Pseudomalus pusillus bulgariensis: Kimsey & Bohart 1991: 269 (cat.). Type locality. Bulgaria: “Bulgarien, (Bilo) ♁ Type und Paratypen Coll. Schulthess (Zürich), Paratypen Coll. m.”. Paratypes, 2 exx: Bilo Bulg. // Paratype Omalus pusillus ssp. bulgariensis Lins. det. Linsenmaier 57 // Ell. pusillus F. det. Mocsáry // NML_ENT GBIF_Chr0001539 and NML_ENT GBIF_Chr0001540. Remarks. The holotype and two paratypes are deposited at ETHZ (Rosa & Greeff 2021)., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on page 72, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Linsenmaier, W. (1959 a) Revision der Familie Chrysididae (Hymenoptera) mit besonderer Berucksichtigung der europaischen Spezies. Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 32 (1), 1 - 232.","Kimsey, L. S. & Bohart, R. M. (1991 [\" 1990 \"]) The Chrysidid Wasps of the World. Oxford University Press, New York, 664 pp.","Rosa, P. & Greeff, M. (2021) The types of Chrysididae (Insecta, Hymenoptera) deposited at the Institute of Entomology of the Swiss Federal Institute of Technology. Zootaxa, 4908 (2), 181 - 204. https: // doi. org / 10.11646 / zootaxa. 4908.2.2"]}

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2023
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49. Omalus Panzer 1801

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Arthropoda, Omalus, Animalia, Biodiversity, Hymenoptera, Taxonomy
Abstract

Genus Omalus Panzer, 1801 Omalus Panzer, 1801: 13. Type species: Chrysis aenea Fabricius, 1787: 284 [= Omalus aeneus (Fabricius, 1787)], by monotypy., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on page 63, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Panzer, G. W. F. (1798 - 1805) Faunae Insectorum Germaniae initia, oder, Deutschlands Insecten. Felseckerschen Buchhandlung, Nurnberg, (1798) Heft 49 - 60; (1801) 80 - 85; (1805), 101 - 107. https: // doi. org / 10.5962 / bhl. title. 15007","Fabricius, J. C. (1787) Mantissa Insectorum sistens eorum species nuper detectas adiectis characteribus genericis, differentiis, specificis, emendationibus, observationibus. Tom. I. Impensis Christ. Gottl. Froft., Hafniae, 368 pp. https: // doi. org / 10.5962 / bhl. title. 11657"]}

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2023
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50. Omalus (Philoctetes) tenerifensis Linsenmaier 1959

Author

Rosa, Paolo, Heim, René, and Bernasconi, Marco Valerio

Subjects
Insecta, Chrysididae, Omalus tenerifensis, Arthropoda, Omalus, Animalia, Biodiversity, Hymenoptera, Taxonomy
Abstract

Omalus (Philoctetes) tenerifensis Linsenmaier, 1959a (Fig. 13A–13D) Omalus (Philoctetes) tenerifensis Linsenmaier, 1959a: 21 (descr.). Philoctetes tenerifensis: Kimsey & Bohart 1991: 258 (cat.). Type locality. Spain (Canary Isl.): “Kanarien. ♁ Type Coll. m. (Tenerife, 24.II.1951)”. Holotype, &female;: Tenerife Las Galletas 24.2.1951 J M Fernandez // Omalus Philoctetes tenerifensis Lins. det. Linsenmaier 1958 (ex type-collection) // NML_ENT GBIF_Chr0001707. Remarks. The type is a female and not a male., Published as part of Rosa, Paolo, Heim, René & Bernasconi, Marco Valerio, 2023, The Palaearctic types of Chrysididae (Insecta, Hymenoptera) deposited in the Linsenmaier collection. Part 4. Elampini: genus Omalus Panzer, 1801, pp. 61-86 in Zootaxa 5297 (1) on page 74, DOI: 10.11646/zootaxa.5297.1.3, http://zenodo.org/record/7989429, {"references":["Linsenmaier, W. (1959 a) Revision der Familie Chrysididae (Hymenoptera) mit besonderer Berucksichtigung der europaischen Spezies. Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 32 (1), 1 - 232.","Kimsey, L. S. & Bohart, R. M. (1991 [\" 1990 \"]) The Chrysidid Wasps of the World. Oxford University Press, New York, 664 pp."]}

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2023
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