Y. Zhang, T Frauenheim, T. Dumitrică, and Z. Tong

ACS Appl. Energy Mater.  6, 9657–9662 (2023)

Using lattice dynamics modeling informed by ab initio calculations and unified heat transport theory, we examine the potential utilization of the diverse crystal structure found in copper telluride (Cu2Te) for on/off thermal conductivity switching. The room-temperature α-phase displays low lattice thermal conductivity (κL) with a significant glass-like transport component as well as anisotropy. When the temperature increases, κL within the ab plane (along c) exhibits a change from 1.05 (0.53) to 3.51 (0.36) W/mK at 600 K in the anisotropic δ-phase. Subsequently, it undergoes another transition from 2.63 (0.29) W/mK in the δ-phase to 1.13 W/mK in the isotropic ε-phase at 760 K. The large variations in κL indicate that both the temperature-dependent phases and their anisotropy are promising attributes for thermal energy control.