Investigation on the phase-transition-induced hysteresis in the thermal transport along the c-axis of MoTe2

The storage and recall of thermal information can be achieved by a thermal memory, which is a key element in the applications of thermal logic devices. Thermal memories can be experimentally realized by solid-state materials with hysteretic thermal transport properties. Here, by means of the time-domain thermoreflectance method, we observe hysteretic behaviors in the c-axis thermal conductivities of molybdenum ditelluride (MoTe2) in their metastable phases. Supported by the characterizations of Raman modes and electrical resistivity, we infer that this hysteresis is induced by the structural phase transition around 250 K. This thermal hysteresis is dominated by the transportation of phonons and makes it possible to build all-phononic devices based on MoTe2. In addition, the mechanism of phonon scatterings is analyzed quantitatively using Boltzmann transport equation. This study provides a promising material system for applications in integrated phononic devices, topological electronics and thermoelectric materials.