Coherent phonon manipulation in van der Waals Graphene-MoS₂ Hetero-structure

Generally, the difference in the intrinsic lattice structures of the constituent materials inevitably generates interface disorder during the fabrication process, greatly limiting direct experimental observation of the coherent phonon transport. The flexible integration and atomistic interlayer smoothness of van der Waals hetero-structure provide an ideal platform for the coherent phonon transport manipulation. Thus, in this work, using the non-equilibrium molecular dynamics simulations, we investigate the coherent phonon transport in van der Waals graphene-MoS₂ hetero-structure with different stacking order at room temperature. The histogram of the phonon transmissions in different disordered structure exhibits a log-normal distribution, which reveals the localization of the coherent phonons. Furthermore, the optimal stacking order of the graphene and MoS₂ is efficiently identified from tens of thousands of candidates by machine learning. The significantly suppressed of the phonon transmission in the low frequency (<5THz) phonons of the optimized structure lead to a significant reduction (~95%) of the thermal conductance compared with the graphite. Finally, the effects of the temperature and strain effect on the graphite and optimized structures are also discussed.