Theoretical investigation of the phonon spectrum and the lattice thermal conductivity in GeTe

Recently, there has been renewed interest in thermoelectric materials based on germanium telluride, which demonstrate high efficiency in mid-temperature range. This paper discusses the theoretical description of the phonon spectrum and lattice thermal conductivity in GeTe using ab initio methods. Using these methods, the temperature dependence of the lattice thermal conductivity in the rhombohedral phase was calculated and effects of scattering by point defects and nanostructuring were estimated. The modification of the phonon spectrum upon the transition to the high-temperature cubic phase is investigated. The calculated temperature dependences of the lattice thermal conductivity are compared with the available experimental data on GeTe and its solid solutions.