References of "Verstraete, Matthieu"      in Complete repository Arts & humanities   Archaeology   Art & art history   Classical & oriental studies   History   Languages & linguistics   Literature   Performing arts   Philosophy & ethics   Religion & theology   Multidisciplinary, general & others Business & economic sciences   Accounting & auditing   Production, distribution & supply chain management   Finance   General management & organizational theory   Human resources management   Management information systems   Marketing   Strategy & innovation   Quantitative methods in economics & management   General economics & history of economic thought   International economics   Macroeconomics & monetary economics   Microeconomics   Economic systems & public economics   Social economics   Special economic topics (health, labor, transportation…)   Multidisciplinary, general & others Engineering, computing & technology   Aerospace & aeronautics engineering   Architecture   Chemical engineering   Civil engineering   Computer science   Electrical & electronics engineering   Energy   Geological, petroleum & mining engineering   Materials science & engineering   Mechanical engineering   Multidisciplinary, general & others Human health sciences   Alternative medicine   Anesthesia & intensive care   Cardiovascular & respiratory systems   Dentistry & oral medicine   Dermatology   Endocrinology, metabolism & nutrition   Forensic medicine   Gastroenterology & hepatology   General & internal medicine   Geriatrics   Hematology   Immunology & infectious disease   Laboratory medicine & medical technology   Neurology   Oncology   Ophthalmology   Orthopedics, rehabilitation & sports medicine   Otolaryngology   Pediatrics   Pharmacy, pharmacology & toxicology   Psychiatry   Public health, health care sciences & services   Radiology, nuclear medicine & imaging   Reproductive medicine (gynecology, andrology, obstetrics)   Rheumatology   Surgery   Urology & nephrology   Multidisciplinary, general & others Law, criminology & political science   Civil law   Criminal law & procedure   Criminology   Economic & commercial law   European & international law   Judicial law   Metalaw, Roman law, history of law & comparative law   Political science, public administration & international relations   Public law   Social law   Tax law   Multidisciplinary, general & others Life sciences   Agriculture & agronomy   Anatomy (cytology, histology, embryology...) & physiology   Animal production & animal husbandry   Aquatic sciences & oceanology   Biochemistry, biophysics & molecular biology   Biotechnology   Entomology & pest control   Environmental sciences & ecology   Food science   Genetics & genetic processes   Microbiology   Phytobiology (plant sciences, forestry, mycology...)   Veterinary medicine & animal health   Zoology   Multidisciplinary, general & others Physical, chemical, mathematical & earth Sciences   Chemistry   Earth sciences & physical geography   Mathematics   Physics   Space science, astronomy & astrophysics   Multidisciplinary, general & others Social & behavioral sciences, psychology   Animal psychology, ethology & psychobiology   Anthropology   Communication & mass media   Education & instruction   Human geography & demography   Library & information sciences   Neurosciences & behavior   Regional & inter-regional studies   Social work & social policy   Sociology & social sciences   Social, industrial & organizational psychology   Theoretical & cognitive psychology   Treatment & clinical psychology   Multidisciplinary, general & others     Showing results 1 to 20 of 80 1 2 3 4 5     The psml format and library for norm-conserving pseudopotential data curation and interoperabilityGarcia, Alberto; Verstraete, Matthieu ; Pouillon, Yann et alin Computer Physics Communications (2018)Detailed reference viewed: 24 (4 ULiège) The PseudoDojo: Training and grading a 85 element optimized norm-conserving pseudopotential tableSetten, M. J. Van; Giantomassi, M.; Bousquet, Eric et alin Computer Physics Communications (2018)Detailed reference viewed: 23 (3 ULiège) Thermoelectric properties of heavily-doped Fe2YZ full-Heusler compoundsLemal, Sébastien ; Ricci, Fabio ; Verstraete, Matthieu et alPoster (2017, July 31)Fe2YZ full-Heusler compounds were recently predicted to exhibit very large thermoelectric power factors [Phys. Rev. Lett. 114, 136601 (2015)]. Combining first-principles density functional theory ... [more ▼]Fe2YZ full-Heusler compounds were recently predicted to exhibit very large thermoelectric power factors [Phys. Rev. Lett. 114, 136601 (2015)]. Combining first-principles density functional theory calculations within a hybrid functional approach and Boltzmann semi-classical transport theory, we investigate the limits of the rigid band doping approximation, and the properties of heavily n-type doped full-Heusler Fe2YZ1-xAx compounds. Using a supercell approach and including explicit dopant impurities, we recover in some cases giant thermoelectric power factors, as previously predicted within the rigid band approximation. In others the effect on the electronic structure is very different from rigid shifts. Interestingly, we find that some systems present a magnetic instability consistent with the Stoner model, and evolve towards a ferromagnetic half-metallic ground state, with a strongly modified power factor. Our results show the promise of the heavily-doped phases of the studied Fe2YZ1-xAx compounds for Seebeck and spin-dependent Seebeck applications. [less ▲]Detailed reference viewed: 158 (8 ULiège) Long-range dispersion forces between molecules subject to attosecond pulses from ab initio calculationsVerstraete, Matthieu Scientific conference (2017, July)The London-van der Waals dispersion forces arising from instantaneously induced dipoles in molecules are a key ingredient in a wide range of phenomena in physics, chemistry, and biology. Therefore, the ... [more ▼]The London-van der Waals dispersion forces arising from instantaneously induced dipoles in molecules are a key ingredient in a wide range of phenomena in physics, chemistry, and biology. Therefore, the ability to control and manipulate dispersion forces between atoms and molecules is of great importance. Because those dispersion interactions depend crucially on the electronic properties of the molecular systems, a simple route to achieve this would consist in manipulating their electronic states. The recent development of ultra-short optical pulses has given researchers unprecedented control over the electronic degrees of freedom. These pulses, tailored in their frequency and envelope, allow the generation of a strongly out of equilibrium population of electronic states. We show how the Hamacker constants characterizing the London-van der Waals interaction between two molecules subject to an optical pulse can be calculated using time-dependent density functional theory (TD-DFT) or standard quantum chemistry methods and present several test cases of molecules subjected to IR and UV attosecond pulses. [less ▲]Detailed reference viewed: 42 (2 ULiège) Origin of the counterintuitive dynamic charge in the transition metal dichalcogenidesPike, Nicholas ; Van Troeye, Benoit; Dewandre, Antoine et alin Physical Review B (2017), 95Despite numerous studies of transition metal dichalcogenides, the diversity of their chemical bonding characteristics and charge transfer is not well understood. Based on density functional theory we ... [more ▼]Despite numerous studies of transition metal dichalcogenides, the diversity of their chemical bonding characteristics and charge transfer is not well understood. Based on density functional theory we investigate their static and dynamic charges. The dynamic charge of the transition metal dichalcogenides with trigonal symmetry are anomalously large, while in their hexagonally symmetric counterparts, we even observe a counterintuitive sign, i.e., the transition metal takes a negative charge, opposite to its static charge. This phenomenon, so far never remarked on or analyzed, is understood by investigating the perturbative response of the system and by investigating the hybridization of the molecular orbitals near the Fermi level. Furthermore, a link is established between the sign of the Born effective charge and the process of π backbonding from organic chemistry. Experiments are proposed to verify the calculated sign of the dynamical charge in these materials. Employing a high-throughput search we also identify other materials that present counterintuitive dynamic charges. [less ▲]Detailed reference viewed: 84 (13 ULiège) Origin of the Counterintuitive Dynamic Charge in the Transition Metal DichalcogenidesPike, Nicholas ; Dewandre, Antoine ; Van Troeye, Benoit et alScientific conference (2017, March)Our recent first-principles calculations of the electronic and vibrational properties of the hexagonal transition-metal dichalcogenides reveal that their Born effective charges display a counterintuitive ... [more ▼]Our recent first-principles calculations of the electronic and vibrational properties of the hexagonal transition-metal dichalcogenides reveal that their Born effective charges display a counterintuitive sign when compared to most other materials or transition-metal dichalcogenides with trigonal symmetry. We determine the origin of this counterintuitive sign by calculating the electronic, vibrational, and optical properties of these systems. We show that the sign of the Born effective charge is directly related to the electric field response of the electronic density, and, in turn, to the bonding characteristics of the material.There is a filled anti-bonding molecular orbital at the Fermi level, which is localized on the transition-metal atom and corresponds to a form of solid state $\pi$ back-bonding in these material. We propose a method of determining if other materials display a similar counterintuitive sign, based on their bonding characteristics, and propose experiments which could measure the sign of the Born effective charge using different spectroscopies. [less ▲]Detailed reference viewed: 89 (0 ULiège) Zhao et al. ReplyZhao, J. Z.; Fan, W.; Verstraete, Matthieu et alin Physical Review Letters (2017), 118(23), 239602Detailed reference viewed: 19 (2 ULiège) Erratum:Temperature dependence of the electronic structure of semiconductors and insulators[J. Chem. Phys. 143, 102813 (2015)]Poncé, S.; Gillet, Y.; Laflamme Janssen, J. et alin Journal of Chemical Physics (2017), 146(9), 099901Detailed reference viewed: 14 (1 ULiège) Conflicting evidence for ferroelectricityD'Avino, Gabriele; Souto, Manuel; Masino, Matteo et alin Nature (2017), 547(7662), 9--10Detailed reference viewed: 41 (3 ULiège) Quantitative Agreement between Electron-Optical Phase Images of $WSe_2$ and Simulations Based on Electrostatic Potentials that Include Bonding EffectsBorghardt, S.; Winkler, F.; Zanolli, Zeila et alin Physical Review Letters (2017), 118Detailed reference viewed: 89 (8 ULiège) Coupled Boltzmann Equation Solver: Effects of the Electron-Phonon Interaction on the Transport CoefficientsPike, Nicholas ; Dewandre, Antoine ; Verstraete, Matthieu Scientific conference (2016, September 22)Recent experimental and theoretical calculations point to a complex interplay between the electron and phonon baths in a wide variety of materials [1,2]. We propose a method of coupling the Boltzmann ... [more ▼]Recent experimental and theoretical calculations point to a complex interplay between the electron and phonon baths in a wide variety of materials [1,2]. We propose a method of coupling the Boltzmann equations for the electron and phonon baths within the relaxation time approximation which we use to calculate the thermoelectric transport coefficients. Our model for the coupled Boltzmann Equation solver includes analytic models, including ${\bf k \cdot p}$ Hamiltonians and tight-binding Hamiltonians, for both the electron and phonon energies and analytic models for the electron and phonon relaxation mechanisms. From these calculations we hope to better understand the role and interplay of electron-phonon and phonon-phonon interactions on the thermoelectric transport coefficients. [1] - Phys. Rev. Lett. ${\bf 114}$, 115901 (2015). [2] - PNAS ${\bf 112}$, 14777-14782 (2015). [less ▲]Detailed reference viewed: 255 (3 ULiège) Competition of phonon and magnon effects in the temperature dependence of spinwave stiffnessOstler, Thomas ; Verstraete, Matthieu ; Di Gennaro, Marco et alConference (2016, September 21)Magnons are the elementary magnetic excitations in ordered solids. Understanding such collective excitations is important for a number of technologically relevant fields, such as, magnonics [1] or spin ... [more ▼]Magnons are the elementary magnetic excitations in ordered solids. Understanding such collective excitations is important for a number of technologically relevant fields, such as, magnonics [1] or spin caloritronics [2]. The central interactions in spin caloritronics are the couplings of phonons with electrons and spin degrees of freedom. Furthermore, understanding the effects of temperature on the phonon and spin degrees of freedom adds a further complexity. In the present work we have developed a multiscale model of ferromagnetic materials and demonstrate the effect of temperature dependent phonon displacements on the magnons spectra. Our results show that the for Fe and Ni the effect of phonon displacements acts to reduce the Curie temperature, whereas for Permalloy the opposite is true due to an increased long-ranged exchange interaction. This increased exchange interaction results in an increasing spin-wave stiffness with increasing temperature, overcoming the usual decrease due to magnon softening. To determine the effects of increasing the phonon temperature we have developed a multiscale model whereby we begin by calculating the thermal displacement of phonons, $\sqrt{\langle u^2(T) \rangle}$, calculated using the phonopy software package [3] using electronic ground state and phonon properties determined using the ABINIT software package [4]. Then the exchange constants are determined using the SPRKKR package [5]. Finally, we use linear spin wave theory to determine the effect of the phonon temperature on the exchange alone, demonstrating an increasing frequency of the acoustic magnon branch. We take into account the thermal effects of the magnetic system through the use of the atomistic spin dynamics approach. Magnon softening due to thermal effects demonstrates a more modest increase in the exchange stiffness (over the purely phononic effect), however, an overall increase is still observed. \newline \newline [1] A. V. Chumak, V. I. Vasyuchka, A. A. Serga, and B. Hillebrands, Nature Physics, {\bf 11}, 453–461 (2015). \newline [2] G. E. W. Bauer, E. Saitoh, and B. J. van Wees, Nature Materials {\bf 11}, 391 (2012). \newline [3] Atsushi Togo and Isao Tanaka, Scr. Mater., {\bf 108}, 1-5 (2015) \newline [4] X. Gonze \textit{et al.} Computer Physics Communications {\bf 180}, 2582-2615 (2009). \newline [5] T. Huhne \textit{at al.} Physical Review B, {\bf 58}, 10236 (1998). [less ▲]Detailed reference viewed: 247 (4 ULiège) Vibrations in the Flat Land- A Study of the Vibrational Properties of the Transition-Metal DichalcogenidesPike, Nicholas ; Dewandre, Antoine ; Verstraete, Matthieu et alScientific conference (2016, September 03)Calculations of the vibrational properties of the transition-metal dichalcoginides depend critically on the lattice parameters, symmetries of the underlying system, and the non-local dispersive ... [more ▼]Calculations of the vibrational properties of the transition-metal dichalcoginides depend critically on the lattice parameters, symmetries of the underlying system, and the non-local dispersive interaction. Here we present phonon band structure calculations, dielectric tensors, elastic tensors, and Born Effective Charges for the transition-metal dichalcogenides $MoS_2$, $MoSe_2$, $MoTe_2$, $WS_2$, $WSe_2$, $NbS_2$, and $NbSe_2$. We systematically investigate the role of the long-range $e^⁻$-$e^⁻$ interaction, spin-orbit coupling, and pseudo-potential approximation, and highlight their importance on the TMD structural and vibrational properties. We find that the phonon spectrum, calculated with the help of a Grimme's D3 non-local Van der Waals interaction depends strongly on the accuracy of the lattice parameters and slightly on the addition of the non-local Van der Waals interaction in the phonon frequency itself. We also find that the sign of the Born Effective Charges on each atom in the Hexagonal TMDs are the opposite of similarly structured compounds. We explore reasons as to why this occurs. Additionally, our calculation of the dielectric tensor and elastic tensor allow us to describe the mechanical properties of the system which are necessary to know for future device applications. [less ▲]Detailed reference viewed: 499 (1 ULiège) Boltzmann Transport Calculations in Systems with Electron-phonon CouplingPike, Nicholas ; Dewandre, Antoine ; Di Gennaro, Marco et alScientific conference (2016, June 07)Recent experimental and theoretical calculations point to a complex interplay between the electron and phonon baths in a wide variety of materials [1,2]. We propose a method of coupling the Boltzmann ... [more ▼]Recent experimental and theoretical calculations point to a complex interplay between the electron and phonon baths in a wide variety of materials [1,2]. We propose a method of coupling the Boltzmann equations for the electron and phonon baths within the relaxation time approximation to describe the changes in the electron and phonon distributions and thus calculate the thermoelectric transport coefficients. Our model for the coupled system will include tight-binding and ${\bf k \cdot p}$ Hamiltonians for both the electron and phonon energies and analytic calculations for the electron and phonon relaxation mechanisms. From these calculations we hope to better understand the role and interplay of electron-phonon and phonon-phonon interactions on the thermoelectric transport coefficients. [1] - Phys. Rev. Lett. ${\bf 114}$, 115901 (2015). [2] - PNAS ${\bf 112}$, 14777-14782 (2015). [less ▲]Detailed reference viewed: 217 (6 ULiège) Coupling the Electron and Phonon Baths via the Boltzmann Transport EquationsPike, Nicholas ; Dewandre, Antoine ; Di Gennaro, Marco et alPoster (2016, April 03)Detailed reference viewed: 180 (6 ULiège) Ab initio phonon limited transportVerstraete, Matthieu Speech/Talk (2016)We revisit the thermoelectric (TE) transport properties of two champion materials, PbTe and SnSe, using fully first principles methods. In both cases the performance of the material is due to subtle ... [more ▼]We revisit the thermoelectric (TE) transport properties of two champion materials, PbTe and SnSe, using fully first principles methods. In both cases the performance of the material is due to subtle combinations of structural effects, scattering, and phase space reduction. In PbTe anharmonic effects are completely opposite to the predicted quasiharmonic evolution of phonon frequencies and to frequently (and incorrectly) cited extrapolations of experiments. This stabilizes the material at high T, but also tends to enhance its thermal conductivity, in a non linear manner, above 600 Kelvin. This explains why PbTe is in practice limited to room temperature applications. SnSe has recently been shown to be the most efficient TE material in bulk form. This is mainly due to a strongly enhanced carrier concentration and electrical conductivity, after going through a phase transition from 600 to 800 K. We calculate the transport coefficients as well as the defect concentrations ab initio, showing excellent agreement with experiment, and elucidating the origin of the double phase transition as well as the new charge carriers. AH Romero, EKU Gross, MJ Verstraete, and O Hellman PRB 91, 214310 (2015) O. Hellman, IA Abrikosov, and SI Simak, PRB 84 180301 (2011) [less ▲]Detailed reference viewed: 169 (3 ULiège) Electron Transport Calculations and Thermoelectric Coefficients of Doped InSbPike, Nicholas ; Di Gennaro, Marco ; Verstraete, Matthieu et alPoster (2016, January 11)Detailed reference viewed: 158 (4 ULiège) Two-step phase transition in SnSe and the origins of its high power factor from first principlesDewandre, Antoine ; Hellman, Olle; Bhattacharya, Sandip et alin Physical Review Letters (2016), 117Detailed reference viewed: 98 (5 ULiège) Strain-induced effects in the electronic and spin properties of a monolayer of ferromagnetic GdAg2Correa, A.; Xu, Bin ; Verstraete, Matthieu et alin Nanoscale (2016), 8Detailed reference viewed: 107 (1 ULiège) Quasi-One-Dimensional Metal-Insulator Transitions in Compound Semiconductor SurfacesZhao, J. Z.; Fan, W.; Verstraete, Matthieu et alin Physical Review Letters (2016), 117Detailed reference viewed: 141 (3 ULiège) 1 2 3 4 5