Fabry-Pérot states mediated quantum valley-Hall conductance in a strained graphene system

Abstract

We investigate the valley-dependent transport of a graphene system consisting of a uniaxially stretched graphene sheet connected by two unstrained parts, with the interfaces between the strained and unstrained regions along the zigzag direction. A detailed study on the Fabry-Pérot states in the strained region reveals that they carry opposite lateral currents for different valleys when a bias is applied across the interfaces, namely, a pure valley-Hall current arises in the central region. The transverse valley conductance is determined by the number of resonant states in the strained region at the Fermi energy. Like the quantum Hall effect, when Fermi energy is varied, the valley-Hall conductance exhibits step structures and the longitudinal conductance shows peaks.