Tunneling valley Hall effect driven by tilted Dirac fermions

TL;DR

This paper predicts a tunneling valley Hall effect driven by tilted Dirac fermions in 2D valley materials, enabling strong valley polarization and resonant tunneling for valleytronic applications.

Contribution

It introduces a novel tunneling valley Hall effect mechanism based on Dirac cone tilting, surpassing previous Berry curvature-based effects, and suggests ways to enhance valley polarization.

Findings

TVHE is stronger than Berry curvature-induced effects.

Doping asymmetry enables momentum filtering and valley Hall current.

Resonant tunneling can significantly enhance valley Hall angle.

Abstract

Valleytronics is a research field utilizing a valley degree of freedom of electrons for information processing and storage. A strong valley polarization is critical for realistic valleytronic applications. Here, we predict a tunneling valley Hall effect (TVHE) driven by tilted Dirac fermions in all-in-one tunnel junctions based on a two-dimensional (2D) valley material. Different doping of the electrode and spacer regions in these tunnel junctions results in momentum filtering of the tunneling Dirac fermions, generating a strong transverse valley Hall current dependent on the Dirac-cone tilting. Using the parameters of an existing 2D valley material, we demonstrate that such a TVHE is much stronger than that induced by the intrinsic Berry curvature mechanism reported previously. Finally, we predict that resonant tunneling can occur in a tunnel junction with properly engineered device parameters such as the spacer width and transport direction, providing significant enhancement of the valley Hall angle. Our work opens a new approach to generate valley polarization in realistic valleytronic systems.