Electronic structure and layer-resolved transmission of bilayer graphene nanoribbon in the presence of vertical fields

摘要

Electronic properties of bilayer graphene are distinct from both the conventional two dimensional electron gas and monolayer graphene due to its particular chiral properties and excitation charge carrier dispersions. We study the effect of strain on the electronic structure, the edge states and charge transport of bilayer graphene nanoribbon at zero temperature. We demonstrate a valley polarized quantum Hall effect in biased bilayer graphene when the system is subjected to a perpendicular magnetic field. In this system a topological phase transition from a quantum valley Hall to a valley polarized quantum Hall phase can occur by tuning the interplanar strain. Furthermore, we study the layer-resolved transport properties by calculating the layer polarized quantity by using the recursive Green's function technique and show that the resulting layer polarized value confirms the obtained phases. These predictions can be verified by experiments, and our results demonstrate the possibility for exploiting strained bilayer graphene in the presence of external fields for electronics and valleytronics devices.