Perfect valley filter in strained graphene with single barrier region

TL;DR

This paper proposes a single barrier graphene device with uniaxial strain and magnetic fields that can generate pure valley-polarized current, potentially realizable with current technology.

Contribution

It introduces a novel single barrier system that achieves pure valley polarization in graphene using strain and magnetic fields, with experimentally feasible parameters.

Findings

Achieves valley-polarized current with zero reflection from one valley.

Maximum conductance for the valley-polarized current.

Parameters are within experimental feasibility.

Abstract

We present a single barrier system to generate pure valley-polarized current in monolayer graphene. A uniaxial strain is applied within the barrier region, which is delineated by localized magnetic field created by ferromagnetic stripes at the regions boundaries. We show that under the condition of matching magnetic field strength, strain potential, and Fermi energy, the transmitted current is composed of only one valley contribution. The desired valley current can transmit with zero reflection while the electrons from the other valley are totally reflected. Thus, the system generates pure valley-polarized current with maximum conductance. The chosen parameters of uniaxial strain and magnetic field are in the range of experimental feasibility, which suggests that the proposed scheme can be realized with current technology.