Weyl Semimetal Path to Valley Filtering in Graphene

TL;DR

This paper introduces a novel device coupling graphene with a Weyl semimetal, enabling robust valley filtering through bulk properties without requiring edge shaping, advancing valleytronics applications.

Contribution

It presents a new bulk-based valley filter device using graphene and Weyl semimetal coupling, distinct from edge-based methods.

Findings

Device acts as a robust valley filter

Selective current draw in one valley

No need for edge shaping or specific dimensions

Abstract

We propose a device in which a sheet of graphene is coupled to a Weyl semimetal, allowing for the physical access to the study of tunneling from two-dimensional to three dimensional massless Dirac fermions. Due to the reconstructed band structure, we find that this device acts as a robust valley filter for electrons in the graphene sheet. We show that, by appropriate alignment, the Weyl semimetal draws away current in one of the two graphene valleys while allowing current in the other to pass unimpeded. In contrast to other proposed valley filters, the mechanism of our proposed device occurs in the bulk of the graphene sheet, obviating the need for carefully shaped edges or dimensions.