Showing results 1 to 20 of 41
  First-principles study of transport properties in Os and OsSiXu, Bin  ; Verstraete, Matthieu in Physical Review. B : Condensed Matter (2013), 87 Detailed reference viewed: 14 (1 ULg)Ab initio calculation of spin-dependent electron-phonon coupling and transport in iron and cobaltVerstraete, Matthieu in Journal of Physics : Condensed Matter (2013), 25 The spin-dependent coupling between electrons and phonons in ferromagnetic Fe and Co is calculated from first principles in a collinear-spin formalism. The added spin polarization is fundamental for the ... [more ▼] The spin-dependent coupling between electrons and phonons in ferromagnetic Fe and Co is calculated from first principles in a collinear-spin formalism. The added spin polarization is fundamental for the correct representation of the phonons, but also to obtain good transport properties, and permits the decomposition (e.g. of the resistivity) into the contributions of majority and minority spin. In Fe the minority spin coupling is only about 50\% more important, but in Co the coupling between phonons and minority spin electrons is an order of magnitude larger than majority, and both are strongly anisotropic. [less ▲] Detailed reference viewed: 23 (2 ULg)Ab initio thermoelectric propertiesXu, Bin ; Diakhate, Momar ; et alConference (2012, November) Detailed reference viewed: 40 (5 ULg)Calculation of Thermoelectric Properties from First-PrinciplesXu, Bin ; Verstraete, Matthieu Poster (2012, July) Detailed reference viewed: 17 (4 ULg)First-Principles Seebeck Calculation: Implementing a general formula for the calculation of the Seebeck coefficient from first-principlesXu, Bin ; Ghosez, Philippe ; Verstraete, Matthieu Conference (2012, May) Detailed reference viewed: 12 (3 ULg)Implementation of Density-Functional Perturbation Theory within ABINIT: Proj ector Augmented-Waves and Spin-Orbit; Verstraete, Matthieu ; et alin AIP Conference Proceedings (2012), 1504 Detailed reference viewed: 8 (1 ULg)Thermopower in oxide heterostructures: The importance of being multiple-band conductors; ; Verstraete, Matthieu et alin Physical Review. B, Condensed Matter and Materials Physics (2012) Detailed reference viewed: 3 (0 ULg)Aluminum Conducts Better than Copper at the Atomic Scale: A First-Principles Study of Metallic Atomic Wires; ; et al in ACS Nano (2012) Detailed reference viewed: 3 (0 ULg)Functionality in single-molecule devices: Model calculations and applications of the inelastic electron tunneling signal in molecular junctions; ; Verstraete, Matthieu et alin Journal of Chemical Physics (2012), 136 We analyze how functionality could be obtained within single-molecule devices by using a combination of non-equilibrium Green's functions and ab initio calculations to study the inelastic transport ... [more ▼] We analyze how functionality could be obtained within single-molecule devices by using a combination of non-equilibrium Green's functions and ab initio calculations to study the inelastic transport properties of single-molecule junctions. First, we apply a full non-equilibrium Green's function technique to a model system with electron-vibration coupling. We show that the features in the inelastic electron tunneling spectra (IETS) of the molecular junctions are virtually independent of the nature of the molecule-lead contacts. Since the contacts are not easily reproducible from one device to another, this is a very useful property. The IETS signal is much more robust versus modifications at the contacts and hence can be used to build functional nanodevices. Second, we consider a realistic model of a organic conjugated molecule. We use ab initio calculations to study how the vibronic properties of the molecule can be controlled by an external electric field which acts as a gate voltage. The control, through the gate voltage, of the vibron frequencies and (more importantly) of the electron-vibron coupling enables the construction of functionality: nonlinear amplification and/or switching is obtained from the IETS signal within a single-molecule device. [less ▲] Detailed reference viewed: 13 (1 ULg)First-principles study of thermoelectric properties in SrTiO3 and FeSb2Xu, Bin ; Diakhate, Momar ; Verstraete, Matthieu et alPoster (2011, October) Detailed reference viewed: 25 (2 ULg) Thermodynamic, thermoelectric, and magnetic properties of FeSb2: A combined first-principles and experimental studyDiakhate, Momar ; Herman, Raphaël ; Verstraete, Matthieu in Physical Review. B : Condensed Matter (2011), 84 Detailed reference viewed: 41 (11 ULg)First-Principles Study of Electron-Phonon Coupling in STO and 2DEGXu, Bin ; Verstraete, Matthieu ; Ghosez, Philippe Conference (2011, May) Detailed reference viewed: 9 (1 ULg)Study of Thermoelectric Properties of n-type Doped STO from Linear Response TheoryXu, Bin ; Verstraete, Matthieu Poster (2011, April) Detailed reference viewed: 11 (0 ULg)Thermodynamic, thermoelectric, and magnetic properties of FeSb2: A combined first-principles and experimental studyDiakhate, Momar ; Hermann, Raphaël ; et alin Physical Review (2011), 84(12), We analyze the thermodynamic, magnetic, and transport properties of the narrow band-gap semiconductor FeSb2 using density functional theory calculations corroborated by nuclear inelastic spectroscopy and ... [more ▼] We analyze the thermodynamic, magnetic, and transport properties of the narrow band-gap semiconductor FeSb2 using density functional theory calculations corroborated by nuclear inelastic spectroscopy and ultrasound experiments. The vibrational properties (phonon spectrum density of states, heat capacity) and elastic constants are computed through response function calculations and are in good agreements with the measurements. The electron-phonon coupling effects are also studied. The estimations of linewidth broadening due to electron-phonon coupling along the high-symmetry directions in the first Brillouin zone are given. The linewidth broadening reaches the largest value for Fe optical modes in the vicinity of the X[0.5,0,0] point. The broadening, when compared to those obtained at the other symmetry points, differs by up to two orders of magnitude. From the Boltzmann theory applied to our electronic band structure, we investigate the electrical transport properties. It is found that a purely electronic structure description is incompatible with the record value of the Seebeck coefficient experimentally observed at T approximate to 12 K. The diamagnetic to paramagnetic crossover at a temperature around 100 K is also described from the calculation of the magnetic susceptibility, and results compare well with experiment. [less ▲] Detailed reference viewed: 9 (2 ULg)Electronic properties of the Mg2Si thermoelectric material investigated by linear-response density-functional theory; Verstraete, Matthieu ; et alin Computational Materials Science (2011), 50(3), 847-851 This paper presents Density-Functional Perturbation Theory (DFPT) calculations on the electronic, vibrational, and electron–phonon (EP) coupling properties of the Mg2Si thermoelectric compound. The DFPT ... [more ▼] This paper presents Density-Functional Perturbation Theory (DFPT) calculations on the electronic, vibrational, and electron–phonon (EP) coupling properties of the Mg2Si thermoelectric compound. The DFPT yields very satisfactory results for the electronic and vibrational properties when compared to experiment. Regarding the EP interactions, as far as we know, they have never been reported so far. We show that the EP interactions in Mg2Si mainly involve the silicon atom. This result explains the improvement of the thermoelectric properties of Mg2Si using a solid solution Mg2Si1−xAx, where A is a heavier atom than Si. By guiding the choice of the substitution site, the study of the EP coupling properties could be used in the search of new thermoelectric materials based on solid solutions. [less ▲] Detailed reference viewed: 49 (6 ULg)A theoretical approach to iron-based superconductorsVerstraete, Matthieu ; in Annalen der Physik (2011), 523 Detailed reference viewed: 20 (2 ULg)Nonlinear response in Density Functional Theory: LDA versus exact; ; et al in Physical Review. A (2011), 83 We present a local density approximation (LDA) for one-dimensional (1D) systems interacting via the soft-Coulomb interaction based on quantum Monte Carlo calculations. Results for the ground-state ... [more ▼] We present a local density approximation (LDA) for one-dimensional (1D) systems interacting via the soft-Coulomb interaction based on quantum Monte Carlo calculations. Results for the ground-state energies and ionization potentials of finite 1D systems show excellent agreement with exact calculations obtained by exploiting the mapping of an N-electron system in d dimensions onto a single electron in N×d dimensions, properly symmetrized by the Young diagrams. We conclude that 1D LDA is of the same quality as its three-dimensional (3D) counterpart, and we infer conclusions about 3D LDA. The linear and nonlinear time-dependent responses of 1D model systems using LDA, exact exchange, and the exact solution are investigated and show very good agreement in both cases, except for the well-known problem of missing double excitations. Consequently, the 3D LDA is expected to be of good quality beyond the linear response. In addition, the 1D LDA should prove useful in modeling the interaction of atoms with strong laser fields, where this specific 1D model is often used. [less ▲] Detailed reference viewed: 67 (4 ULg)Rare-earth surface alloying: a new phase for GdAu$_2$; Verstraete, Matthieu ; et alin Physical Review Letters (2010), 105 Detailed reference viewed: 47 (6 ULg)Phases of Polonium via Density Functional TheoryVerstraete, Matthieu in Physical Review Letters (2010), 104 Detailed reference viewed: 62 (10 ULg)ABINIT: First-principles approach to material and nanosystem properties; ; et al in Computer Physics Communications (2009), 180 ABINIT allows one to study, from first-principles, systems made of lectrons and nuclei (e.g. periodic solids, molecules, nanostructures, etc.), on the basis of Density-Functional Theory (DFT) and many ... [more ▼] ABINIT allows one to study, from first-principles, systems made of lectrons and nuclei (e.g. periodic solids, molecules, nanostructures, etc.), on the basis of Density-Functional Theory (DFT) and many-Body Perturbation Theory. beyond the computation of the total energy, charge density and electronic structure of such systems, ABINIT also implements many dynamical, dielectric, thermodynamical, mechanical, or electronic properties, at different levels of approximation. The present paper provides an exhustive account of the capabilities of ABINIT. It should be helpful to scienttists that are not familirized with ABINIT, as well as to already regular users. First, we give a broad overview of ABINIT, including the list of the capabilities and how to access them. Then, we present in more details the recent, advance, developments of ABINIT, with adequate references to the underlying theory, as well as the relevant input variables, tests and, if available, ABINIT tutorials. [less ▲] Detailed reference viewed: 194 (11 ULg) |
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