Abstract
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.
Highlights
The microelectronic devices capable of high-speed computing have a broad range of applications nowadays
A theoretical model of thermal memory has already been proposed in a nonlinear lattice,[3] but the majority of experimental realizations in this field are based on the phase change materials (PCMs) with hysteretic thermal properties.[4,5,6]
We found that time-domain thermoreflectance (TDTR) was quite suitable for the κc measurements of thin flakes with small and irregular dimensions comparing to other commercial instruments
Summary
The microelectronic devices capable of high-speed computing have a broad range of applications nowadays. A theoretical model of thermal memory has already been proposed in a nonlinear lattice,[3] but the majority of experimental realizations in this field are based on the phase change materials (PCMs) with hysteretic thermal properties.[4,5,6] In some traditional PCMs, e.g., vanadium dioxide (VO2), the hystereses of thermal conductivities are mainly resulted from the hysteretic transportations of electrons during the phase transitions.[7, 8] Due to the weak electron-phonon couplings, these PCMs may be incompatible with the ‘all-phononic devices’.9. It is necessary to explore more materials with simple chemical components to realize the hysteretic behavior of thermal transport that is dominantly contributed by phonons
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