A valley valve and electron beam splitter

TL;DR

This paper demonstrates a novel valley valve and electron beam splitter in bilayer graphene, utilizing valley-specific phenomena for potential scalable quantum transport applications.

Contribution

It introduces gate-controlled valley kink states in bilayer graphene, enabling a valley valve and tunable electron beam splitter with high on/off ratio and magnetic field control.

Findings

Achieved ballistic valley Hall kink states in bilayer graphene.

Demonstrated gate-controlled current transmission with a four-kink router.

Realized a tunable coherent electron beam splitter.

Abstract

Developing alternative paradigms of electronics beyond silicon technology requires the exploration of fundamentally new physical mechanisms, such as the valley specific phenomena in hexagonal two-dimensional materials. We realize ballistic valley Hall kink states in bilayer graphene and demonstrate gate-controlled current transmission in a four-kink router device. The operations of a waveguide, a valve and a tunable electron beam splitter are demonstrated. The valley valve exploits the valley-momentum locking of the kink states and reaches an on/off ratio of 8 at zero magnetic field. A magnetic field enables a full-ranged tunable coherent beam splitter. These results pave the path to building a scalable, coherent quantum transportation network based on the kink states.