Thermal rectification of graphene on substrates with inhomogeneous stiffness

Abstract

Thermal rectification is of great importance in various thermal management and thermal logic applications, where heat flux runs preferentially in one direction over the opposite one. This phenomenon is mostly reported in previous simulations and experiments by introducing asymmetry shape-tailoring, defects and doping, etc. However, these approaches break the structure of the heat conductor. In this paper, we report thermal rectification induced by modulating the substrate stiffness on the supported graphene, which preserves structural integrity of graphene, making it reusable. Our results show that the heat flux prefers to flow toward the stiffer part of a substrate. The maximum thermal rectification factor can reach ∼48% by using the ideal substrate model prediction. Moreover, a wide range thermal rectification factor of 3.5%–22.7% can be achieved by using a sandwich model. These phenomena are explained by phonon vibration spectra and excitation simulations. Our results should be of great help for understanding the modulation of thermal rectification in supported material and shed light on the design of a new thermal logic gate and thermal management devices.