MD simulations of molybdenum disulphide (MoS2): Force-field parameterization and thermal transport behavior

In this article, we have investigated the anisotropic nature of thermal transport in molybdenum disulphide using molecular dynamics simulations. At first, a force field has been validated with respect to crystal structure and experimental vibrational spectra of MoS2. Thereafter, non-equilibrium MD simulations have been performed in two perpendicular directions (along as well as across the basal planes) to study thermal transport behavior. At room temperature, our results show an anisotropic factor of ∼4 in the values of thermal conductivity along two studied directions, which is in good agreement with recent experiments on MoS2 thin films. However, the predicted values of thermal conductivity are about an order of magnitude higher with respect to experiments. The reasoning behind these differences has been discussed in terms of layer disorder and the large number of grain boundary interfaces in experimental thin films, which consisted of nano-crystalline MoS2 grains with a predominant parallel or perpendicular basal plane orientation. Incorporation of phonon scattering via structure disorder and boundary interfaces were identified as further directions for the model refinement.