A significant enhancement in thermal conductivity of plastic crystals under compressive strain by deep potential molecular dynamics

Abstract

The unique properties of plastic crystals highlight their potential for use in solid-state refrigeration. However, their practical applications are limited by thermal hysteresis due to low thermal conductivity. In this study, the effect of compressive strain on the thermal transport properties of [(CH3)4N][FeCl4] was investigated using molecular dynamic simulation with a deep potential. It is found that the thermal conductivities along the [100], [010], [001], [101], and [011] directions are enhanced under 9% strain by 110%, 580%, 114%, 408%, and 268%, respectively. The underlying mechanisms are analyzed through vibrational density of states and spectral energy densities. The enhancement in thermal conductivity is primarily due to reduced phonon scattering. These findings offer theoretical insights for the practical application of plastic crystals in thermal management systems.