Lattice Dynamics and Specific Heat of $\alpha$ - GeTe: a theoretical and experimental study

Abstract

We extend recent \textit{ab initio} calculations of the electronic band structure and the phonon dispersion relations of rhombohedral GeTe to calculations of the density of phonon states and the temperature dependent specific heat. The results are compared with measurements of the specific heat. It is discovered that the specific heat depends on hole concentration, not only in the very low temperature region (Sommerfeld term) but also at the maximum of $C_p/T^3$ (around 16 K). To explain this phenomenon, we have performed \textit{ab initio} lattice dynamical calculations for GeTe rendered metallic through the presence of a heavy hole concentration ($p$ $\sim$ 2$\times$ 10${}^{21}$ cm${}^{-3}$). They account for the increase observed in the maximum of $C_p/T^3$.

8 pages, 7 figures, ref. 19 corrected

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Cited by in corpus (7)

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• Flux periodic oscillations and phase-coherent transport in GeTe nanowire-based devices
• Effect of characteristic size on the collective phonon transport in crystalline GeTe
• Non-thermal transport of energy driven by photoexcited carriers in switchable solid states of GeTe
• Sommerfeld-Bethe analysis of ZT in inhomogeneous thermoelectrics
• Ultrafast modulation of covalency in GeTe driven by a ferroelectric soft mode