抄録
A graphene/hexagonal boron nitride (hBN) heterobilayer (HBL) is among two-dimensional van der Waals heterostructures. In the present paper, the effects of interlayer bonds in a graphene/hBN HBL on its thermal conductivity (TC) are addressed using molecular dynamics (MD) simulation. The TC is estimated by the method of nonequilibrium MD. It is shown that the TC of a graphene/hBN HBL sharply decreases if only a few interlayer bonds exist, and continues to gradually decrease with increasing the density of the interlayer bonds up to about 25 %. However, it starts to gradually increase if the density of the interlayer bonds exceeds about 25 %. Namely, there exists a minimum TC of the HBL. The reduction of the TC occurs because the interlayer bonds work as phonon scatterers. On the other hand, its increase occurs because the rigidity of the HBL is enhanced via interlayer bonds. Its minimum appears resulting from the balance between the both actions of the interlayer bonds. In order to confirm such an interpretation, the phonon density of states (DOSs) in the HBLs with/without interlayer bonds are examined in details.