Orientation Dependent Thermal Conductance in Single-Layer MoS2

Abstract: We investigate the thermal conductivity in the armchair and zigzag MoS${2}$ nanoribbons, by combining the non-equilibrium Green's function approach and the first-principles method. A strong orientation dependence is observed in the thermal conductivity. Particularly, the thermal conductivity for the armchair MoS${2}$ nanoribbon is about 673.6 Wm$^{-1}$K$^{-1}$ in the armchair nanoribbon, and 841.1 Wm$^{-1}$K$^{-1}$ in the zigzag nanoribbon at room temperature. By calculating the Caroli transmission, we disclose the underlying mechanism for this strong orientation dependence to be the fewer phonon transport channels in the armchair MoS${2}$ nanoribbon in the frequency range of [150, 200] {cm$^{-1}$}. Through the scaling of the phonon dispersion, we further illustrate that the thermal conductivity calculated for the MoS${2}$ nanoribbon is esentially in consistent with the superior thermal conductivity found for graphene.