References of "Verstraete, Matthieu"
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See detailAb initio phonon limited transport
Verstraete, Matthieu ULg

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 ▲]

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See detailNon-monotonous anisotropy in charge conduction induced by antiferrodistortive transition in metallic SrTiO3
Tao, Qian; Loret, Bastien; Xu, Bin ULg et al

in Physical Review B (2016), 94

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See detailFirst-Principles Study of the Thermoelectric Properties of SrRuO3
Miao, Naihua; Xu, Bin ULg; Bristowe, Nicholas ULg et al

in Journal of Physical Chemistry (2016), 120

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See detailRecent developments in the ABINIT software package
Gonze, X.; Jollet, F.; Araujo, F. Abreu et al

in Computer Physics Communications (2016), 205

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See detailHigh Temperature Ferromagnetism in a GdAg2 Monolayer
Ormaza, M.; Fernandez, L.; Ilyn, M. et al

in Nano Letters (2016), 0(0),

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See detailThermoelectric properties of the unfilled skutterudite FeSb3 from first principles and Seebeck local probes
Lemal, Sébastien ULg; Ngoc, Nguyen; de Boor, Johannes et al

in Physical Review. B: Condensed Matter and Materials Physics (2015), 92

Using a combination of first-principles calculations and experimental transport measurements, we study the electronic and magnetic structure of the unfilled skutterudite FeSb3. We employ the hybrid ... [more ▼]

Using a combination of first-principles calculations and experimental transport measurements, we study the electronic and magnetic structure of the unfilled skutterudite FeSb3. We employ the hybrid functional approach for exchange-correlation. The ground state is determined to be anti-ferromagnetic with an atomic magnetic moment of 1.6 μB/Fe. The Néel temperature Tn is estimated at 6 K, in agreement with experiments which found a paramagnetic state down to 10 K. The ground state is semiconducting, with a small electronic gap of 33 meV, also consistent with previous experiments on films. Charge carrier concentrations are estimated from Hall resistance measurements. The Seebeck coefficient is measured and mapped using a scanning probe at room temperature that yields an average value of 38.6 μV/K, slightly lower than the theoretical result. The theoretical conductivity is analyzed as a function of temperature and concentration of charge carriers. [less ▲]

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See detailTemperature dependence of the electronic structure of semiconductors and insulators
Poncé, S.; Gillet, Y.; Laflamme Janssen, J. et al

in Journal of Chemical Physics (2015), 143(10),

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See detailComputational benchmarking for ultrafast electron dynamics: wavefunction methods vs density functional theory
Oliveira, Micael J. T.; Mignolet, Benoît ULg; Kus, Tomasz et al

in Journal of Chemical Theory and Computation (2015), 11

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See detailThermal conductivity in PbTe from first principles
Romero, A. H.; Gross, E. K. U.; Verstraete, Matthieu ULg et al

in Physical Review B (2015), 91(21), 214310

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See detailReal-space grids and the Octopus code as tools for the development of new simulation approaches for electronic systems
Andrade, Xavier; Strubbe, David; De Giovannini, Umberto et al

in Physical Chemistry Chemical Physics (2015)

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See detailCorrection to Aluminum Conducts Better than Copper at the Atomic Scale: A First-Principles Study of Metallic Atomic Wires
Simbeck, Adam J.; Lanzillo, Nick; Kharche, Neerav et al

in ACS nano (2015), 9(6), 6635--6635

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See detailAb-initio Study of Ferecrystals
Dewandre, Antoine ULg; Verstraete, Matthieu ULg

Poster (2014, September)

Ferecrystals are a new family of compounds first synthesized in 2007 by the group of D. Johnson at the University of Oregon. These materials consist of inter-growths of dichalcogenide and chalcogenide ... [more ▼]

Ferecrystals are a new family of compounds first synthesized in 2007 by the group of D. Johnson at the University of Oregon. These materials consist of inter-growths of dichalcogenide and chalcogenide layers, and can be written as [(M X)_{1+δ} ]_m [T X_2 ]_n where M = Sn, Pb, Sb, Ni and some rare earths; T = Ti, V, Cr, Nb and Ta; X= S and Se. The integers m and n denote the numbers of consecutive formula unit layers in the different components of the inter-growth. The δ parameter reflects the difference of the in-plane cell constants between components of the inter-growth. This family of nanostructured materials shows promising properties for thermoelectric devices. The compounds studied here are [(SnSe)_1.29 ]_{234} [M oSe_2 ]_1 . We performed structural characterisation and examined the transfer of charge at the interface between the two materials. We show that there is a depletion of charge at the interface between the two compo- nents of the heterostructures and that structural distortions of the SnSe layers in the supercell are similar to those observed in slab calculations. [less ▲]

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See detailEffect of hydrostatic pressure on the thermoelectric properties of Bi2 Te3
Ibarra-Hernández, Wilfredo; Verstraete, Matthieu ULg; Raty, Jean-Yves ULg

in Physical Review. B: Condensed Matter and Materials Physics (2014), 90(24), 245204

We use first-principles calculations to understand the behavior of the Seebeck coefficient (S) in Bi2Te3 as a function of isotropic pressure. We perform calculations up to 5 GPa using density functional ... [more ▼]

We use first-principles calculations to understand the behavior of the Seebeck coefficient (S) in Bi2Te3 as a function of isotropic pressure. We perform calculations up to 5 GPa using density functional theory and with thermoelectric properties extracted using Boltzmann transport equations. We find that with the increase in pressure the system becomes more metallic, in agreement with previous calculations on Sb2Te3. For p-type doping the overall behavior is a decrease in S with an increase in pressure. At small values of hole doping (p=1.8×1018cm-3), we obtain an anomalous variation of S under 2 GPa, which is an indication of the electronic topological transition. For n-type doping, S slightly increases with pressure. © 2014 American Physical Society. [less ▲]

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See detailAre Hydrogen-Bonded Charge Transfer Crystals Room Temperature Ferroelectrics?
D'Avino, Gabriele ULg; Verstraete, Matthieu ULg

in Physical Review Letters (2014), 113

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See detailFirst Principles Explanation of the Positive Seebeck Coefficient of Lithium
Xu, Bin ULg; Verstraete, Matthieu ULg

in Physical Review Letters (2014), 112

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See detailDensity Functional Perturbation Theory
Verstraete, Matthieu ULg; Zanolli, Zeila ULg

in Blügel, S.; Helbig, N.; Meden, V. (Eds.) et al Computing Solids: Models, Ab-initio Methods and Supercomputing, Lecture Notes of the 45th Spring School 2014 (2014)

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See detailCumulant expansion for phonon contributions to the electron spectral function
Story, S. M.; Kas, J. J.; Vila, F. D. et al

in Physical Review. B, Condensed Matter and Materials Physics (2014), 90

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See detailAb initio calculation of the thermal conductivity of indium antimonide
Miranda, Alonso L.; Xu, Bin ULg; Hellman, Olle et al

in Semiconductor Science and Technology (2014), 29(12), 124002

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See detailFirst-principles study of the lattice dynamical properties of strontium ruthenate
Miao, Naihua ULg; Bristowe, Nicholas ULg; Xu, Bin et al

in Journal of Physics : Condensed Matter (2014), 26

By means of first-principles calculations, various properties of SrRuO3 are investigated, focusing on its lattice dynamical properties. Despite having a Goldschmidt tolerance factor very close to 1, the ... [more ▼]

By means of first-principles calculations, various properties of SrRuO3 are investigated, focusing on its lattice dynamical properties. Despite having a Goldschmidt tolerance factor very close to 1, the phonon dispersion curves of the high-temperature cubic phase of SrRuO3 show strong antiferrodistortive instabilities. The energetics of metastable phases with different tilt patterns are discussed, concluding that the coupling of oxygen rotation modes with anti-polar Sr motion plays a key role in stabilizing the Pnma phase with respect to alternative rotation patterns. Our systematic analysis confirms previous expectations and contributes to rationalizing better why many ABO3 perovskites, including metallic compounds, exhibit an orthorhombic ground state. The zone-center phonon modes of the Pnma phase have been computed, from which we propose partial reassignment of available experimental data. The full dispersion curves have also been obtained, constituting benchmark results for the interpretation of future measurements and providing access to thermodynamical properties. [less ▲]

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See detailLaAu2 and CeAu2 surface intermetallic compounds grown by high-temperature deposition on Au(111)
Ormaza, M.; Fernandez, L.; Lafuente, S. et al

in Physical Review. B, Condensed Matter and Materials Physics (2013), 88

We report on the crystal structure and electronic bands of LaAu2 and CeAu2 surface intermetallic compounds grown by high-temperature deposition on Au(111). By scanning-tunneling microscopy we study the ... [more ▼]

We report on the crystal structure and electronic bands of LaAu2 and CeAu2 surface intermetallic compounds grown by high-temperature deposition on Au(111). By scanning-tunneling microscopy we study the formation of different alloy phases as a function of growth temperature and lanthanide coverage. We determine the specific growth conditions to achieve monolayers and bilayers of LaAu2 and CeAu2 with high crystalline quality. Due to lattice mismatch with the underlying Au substrate, both LaAu2 and CeAu2 exhibit long-range moire ́ patterns, which can serve as templates for further nanostructure growth. By angle-resolved photoemission we map the two-dimensional band structure of these surface alloys, discussing the nature of the different spectral features in the light of first-principles calculations. [less ▲]

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