Valley-dependent Brewster angles and Goos-Hanchen effect in strained graphene

TL;DR

This paper theoretically explores how local strain engineering in graphene can create valley-polarized currents by exploiting valley-dependent Brewster angles and Goos-Hänchen shifts, enabling valley filtering without external fields.

Contribution

It introduces a method to generate valley-polarized currents in graphene through strain profiles, revealing valley-dependent optical-like phenomena and a new approach to valley filtering.

Findings

Different Brewster-like angles for K and K' valleys.

Valley-dependent Goos-Hänchen shifts in strained graphene.

Potential for strain-induced valley filtering without external fields.

Abstract

We demonstrate theoretically how local strains in graphene can be tailored to generate a valley polarized current. By suitable engineering of local strain profiles, we find that electrons in opposite valleys (K or K') show different Brewster-like angles and Goos-H\"anchen shifts, exhibiting a close analogy with light propagating behavior. In a strain-induced waveguide, electrons in K and K' valleys have different group velocities, which can be used to construct a valley filter in graphene without the need for any external fields.