Lattice dynamics and thermal transport of PbTe under high pressure
Ruihuan Cheng, Xingchen Shen, Stefan Klotz, Zezhu Zeng, Zehua Li, A. Ivanov, Yu Xiao, Li‐Dong Zhao, F. Weber, Yue Chen
Abstract
Understanding the high-pressure lattice dynamics is crucial to modulate the thermal transport in thermoelectric materials beyond the ambient environment. Herein, using molecular dynamics simulations in combination with an accurate machine-learning interatomic potential, we find the well-known double-peak feature of the transverse-optical (TO) mode in PbTe gradually vanishes when pressure is enhanced. An anomalous nonmonotonic pressure dependence of the frequency of the transverse-acoustic phonon in PbTe is computationally reproduced. The longitudinal-acoustic, longitudinal-optical, and TO phonons harden as expected when pressure increases. The theoretical results are compared with inelastic neutron scattering experimental data. We have also calculated the pressure-dependent lattice thermal conductivity and revealed the phonon transport mechanisms.