Thermal transport properties in monolayer GeS

Abstract

Utilizing the first-principle techniques combined with the Boltzmann transport equation, we investigate the thermal transport properties of monolayer GeS. The calculated lattice thermal conductivity κL is fairly low, e.g., 11.76 (12.53) Wm−1K−1 at 300 K, along the x (y) axis, which is much lower than the values for phosphorene, monolayer MoS2, graphene, etc. Our analysis reveals that the low lattice thermal conductivity is resulted from the strong three-phonon scattering process and the low phonon group velocity. Due to the weak anisotropy of GeS, we study the contribution of each phonon branch to the heat transport along x and y axis, and find that the longitudinal acoustic (LA) mode contributes most of the total κL along x axis, while the transverse acoustic (TA) branch has the largest contribution to the total κL along y axis. Additionally, the size dependence of thermal conductivity with respect to the nanoribbon width is also studied for the design of nanometer devices.