First-principles calculation of lattice thermal conductivity in crystalline phase change materials: GeTe, Sb2Te3, and Ge2Sb2Te5 - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Physical Review B: Condensed Matter and Materials Physics (1998-2015) Année : 2017

First-principles calculation of lattice thermal conductivity in crystalline phase change materials: GeTe, Sb2Te3, and Ge2Sb2Te5

Résumé

Thermal transport is a key feature for the operation of phase change memory devices which rest on a fast and reversible transformation between the crystalline and amorphous phases of chalcogenide alloys upon Joule heating. In this paper we report on the ab initio calculations of bulk thermal conductivity of the prototypical phase change compounds Ge 2 Sb 2 Te 5 and GeTe in their crystalline form. The related Sb 2 Te 3 compound is also investigated for the sake of comparison. Thermal conductivity is obtained from the solution of the Boltzmann transport equation with phonon scattering rates computed within density functional perturbation theory. The calculations show that the large spread in the experimental data on the lattice thermal conductivity of GeTe is due to a variable content of Ge vacancies which at concentrations realized experimentally can halve the bulk thermal conductivity with respect to the ideal crystal. We show that the very low thermal conductivity of hexagonal Ge 2 Sb 2 Te 5 of about 0.45 W m −1 K −1 measured experimentally is also resulting from disorder in the form of a random distribution of Ge/Sb atoms in one sublattice.
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Dates et versions

hal-01447023 , version 1 (26-01-2017)

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Davide Campi, Lorenzo Paulatto, Giorgia Fugallo, Francesco Mauri, Marco Bernasconi. First-principles calculation of lattice thermal conductivity in crystalline phase change materials: GeTe, Sb2Te3, and Ge2Sb2Te5. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2017, 95, pp.24311 - 24311. ⟨10.1103/PhysRevB.95.024311⟩. ⟨hal-01447023⟩
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