Tunable lattice thermal conductivity of twisted bilayer MoS₂

We have studied the thermal conductivity (κ) of layered MoS₂, a typical member of the transition metal dichalcogenide (TMDC) materials, using fully atomistic molecular dynamics simulations and Boltzmann transport equation (BTE) based first principles methods. We investigate the tuning of the thermal conductivity with the twist angle between two layers and found a decreasing trend of κ with the increase in the lattice constant of the moiré superlattice. The thermal conductivity at twist angle θ = 21.78° is found to be 72.03 W m^-1 K^-1 and for an angle of 2.87°, it reaches 54.48 W m^-1 K^-1, leading to a 32% reduction in the thermal conductivity. We use first principles calculations based on the BTE for phonons to give a microscopic origin of the decrease in thermal conductivity through anharmonic phonon scattering events and also reaffirm the MD simulation results for the monolayer and bilayer.