Abstract
We employ the recursive green function method to study the transmission through the valley-FET, which is basically a quasi-one-dimensional structure composed of a quantum wire channel of narrow-gap graphene confined by barriers of wide-gap graphene and sandwiched between armchair graphene nanorribbon (AGNR) source and drain. The numerical result confirms that the transmission can be modulated by applying an external in-plane electric field perpendicular to the wire, due to the valley-orbit interaction (VOI) in gapped graphene. The effects of energy gap of barrier graphene, channel length and width, and AGNR length and width are studied. As coherent devices, interference phenomena in valleytronic devices in valley FETs are expected. In particular, the Fabry-Perot resonance and Fano resonance are demonstrated and explanations of their origins are proposed.