Graphene valley filter using a line defect

TL;DR

This paper proposes a graphene valley filter utilizing a line defect that enables near-perfect valley polarization of quasiparticles based on their incident angle, without requiring confinement.

Contribution

It introduces a novel valley filtering method in graphene using a line defect, demonstrated through quantum transport calculations.

Findings

Line defect in graphene acts as an effective valley filter.

High angle incidence quasiparticles are transmitted with near 100% valley polarization.

The filter operates without confinement, simplifying device design.

Abstract

With its two degenerate valleys at the Fermi level, the band structure of graphene provides the opportunity to develop unconventional electronic applications. Herein, we show that electron and hole quasiparticles in graphene can be filtered according to which valley they occupy without the need to introduce confinement. The proposed valley filter is based on scattering off a recently observed line defect in graphene. Quantum transport calculations show that the line defect is semitransparent and that quasiparticles arriving at the line defect with a high angle of incidence are transmitted with a valley polarization near 100%.