• Background

A selection of substrate material is an important problem for application of graphene electric devices, since graphene surfaces is exposed. Recently, h-BN is widely used for graphene transport measurement to obtain good properties, such as high mobility. However, such good properties can be observed for high quality h-BN only. Therefore, the defects in h-BN should play some role to degrade graphene transport properties. I have been interested in the effect of defect in h-BN on the electronic transport of adsorbed graphene.

• First-principles calculations

For this problem, we calculated the electronic structures and transport properties of graphene on h-BN with defects using first-principles calculations based on density functional theory. 

We considered substitutional C impurities and atomic vacancies. Calculated band structures have defect levels and graphene are doped by defects. We also performed the transport simulation based on non-equilibrium Green's function method. Calculated transmission (Landauer conductance) have dip near the defect level and is asymmetric by doping to graphene.

See T. Kaneko and T. Ohno, J. Appl. Phys. 123,124304 (2018).

• Tight binding model simulations

In above work, the C impurity effect becomes negligible when the C impurity is located at the hollow site (center of the six-membered ring). To clarify such effect, a tight binding model based simulations were performed. 

We found that the interference effect of electron in graphene causes negligible small interaction of C impurity at the hollow site. 

See T. Kaneko et al., Phys. Rev. B (2017).