Tunneling valley Hall effect induced by coherent geometric phase

TL;DR

This paper introduces a novel valley Hall effect in $ ext{α-} ext{T}_3$ lattices, where coherent geometric phases induce a transverse valley current controllable by gate voltages, advancing valleytronic device technology.

Contribution

It demonstrates a new geometric phase-resolved tunneling valley Hall effect driven by coherent transmission through electric barriers in $ ext{α-} ext{T}_3$ lattices, enabling electrical control of valley currents.

Findings

Backreflected electrons acquire valley-dependent geometric phases.

Coherent geometric phases cause valley-dependent skew tunneling.

Transverse valley Hall current can be electrically tuned by gate voltages.

Abstract

We propose a geometric phase-resolved tunneling valley Hall effect based on the coherent transmission through two combined electric barriers in $\alpha-\mathcal{T}_3$ lattices. It is shown that the backreflected electrons at the barrier interface may acquire a valley-dependent geometric phase. The coherence of this geometric phase leads to the valley-dependent skew tunneling, which is responsible for the transverse valley current with zero net charge. We further demonstrate that this charge-neutral transverse valley Hall current can be electrically controlled by the gate voltages applied across the two combined barrier regions and is absent when the two barriers are of equal height. Our work opens a new approach to generating the valley Hall effect, suggesting potential applications for valleytronic devices.