Resonant valley filtering of massive Dirac electrons

TL;DR

This paper demonstrates a method to filter massive Dirac electrons by their valley index using a double barrier structure with electric and vector potentials, enabling tunable valleytronic devices.

Contribution

It introduces a novel double barrier setup for valley filtering of massive Dirac electrons and analyzes the resulting energy spectrum and resonant transmission properties.

Findings

Valley-dependent energy gaps can be tuned by potential adjustments.

Resonant transmission peaks are observed for specific energies.

Energy spectrum of superlattice shows tunable band gaps at K and K' points.

Abstract

Electrons in graphene, in addition to their spin, have two pseudospin degrees of freedom: sublattice and valley pseudospin. Valleytronics uses the valley degree of freedom as a carrier of information similar to the way spintronics uses electron spin. We show how a double barrier structure consisting of electric and vector potentials can be used to filter massive Dirac electrons based on their valley index. We study the resonant transmission through a finite number of barriers and we obtain the energy spectrum of a superlattice consisting of electric and vector potentials. When a mass term is included the energy bands and energy gaps at the K and K' points are different and they can be tuned by changing the potential.