Heat Conduction Modulation in Incommensurate Twisted Stacking of Transition-Metal Dichalcogenide

Understanding and controlling heat conduction in twisted transition-metal dichalcogenides (TMDs) is crucial for thermal management in TMDs semiconductor devices and advancements in their thermal functions. Despite the significant tunability reported for interlayer heat conduction in randomly twisted multilayer TMDs, the dependence of heat conduction on the twist angle remains unclear. In this study, the twist-angle-dependent interlayer heat conductance in bilayer WS2 and MoS2 is initially assessed. As a result, the thermal conductance decreases as the twist angle between the two stacked layers increases from the commensurate to incommensurate angles, with particularly strong variation near the commensurate angle. This angle dependence correlates with the frequency shift in the Raman spectrum, indicating interlayer interactions and lattice strain within the metastable, incommensurate twisted bilayer structure. Molecular dynamics analysis attributes the twist-angle-dependent heat conduction to the varying interlayer interactions and the overlap in the vibrational density of states determined by the incommensurate structure.