Temperature Dependent Phonons of Transition- Metal Dichalcogenides Calculated from Spectral Energy Density: Thermal Lattice Conductivity as an Application

Predicting the mechanical and thermal properties of quasi two dimensional transition metal dichalcogenides (TMDs) is an essential task necessary for their implementation in device applications. Although, rigorous density functional theory (DFT) based calculations are able to predict mechanical and electronic properties, mostly they are limited to zero temperature. Classical molecular dynamics (MD) facilitates the investigation of temperature dependent properties, but its performance is highly depend on potential used for defining interactions between atoms. In this study, we calculated temperature dependent phonon properties of single layer TMDs , namely MoS₂, MoSe₂, WS₂, and WSe₂, by utilizing Stillinger-Weber (SW) type potentials with optimized sets of parameters with respect to the first principle results. The phonon lifetimes and contribution of each phonon mode in thermal conductivities in monolayer MoS₂, MoSe₂, WS₂, and WSe₂ are systematically investigated by means of spectral energy density (SED) method. The obtained results from this approach are in good agreement with previously available results from Green-Kubo (GK) method.