A valley beam splitter of massive Dirac electrons

Abstract

We propose an electrically controllable valley beam splitter of massive Dirac electrons through the valley dependent Goos–Hänchen effect. The device consists of a monolayer graphene grown on a substrate and two ferromagnetic stripes with magnetizations directed along the current direction (the x axis). We found that the transmitted K and K′ valley electron beams exit at different longitudinal positions, and they can be separated spatially. The lateral displacements for the K and K′ valley electron beams, as well as their separations, can be enhanced by the transmission resonances formed between the two ferromagnetic stripes. The spatial separation between the K and K′ valley electron beams can reach values up to several thousands of wavelengths, which indicates that we can collect the two beams at different positions in the experiment. Our results can stimulate further experimental investigation of valley beam splitter in gapped graphene.