Observation of time-reversal symmetric Hall effect in graphene-WSe2 heterostructures at room temperature

TL;DR

This study demonstrates a room-temperature, time-reversal symmetric Hall effect in graphene/WSe2 heterostructures, tunable by electric fields, driven by strain-induced band anisotropy and symmetry breaking.

Contribution

First experimental observation of a dissipative, time-reversal symmetric Hall effect in graphene heterostructures, with theoretical analysis linking it to strain-induced anisotropic bands.

Findings

Hall effect persists at room temperature

Hall signal can be tuned by electric field

Strain and lattice mismatch induce band anisotropy

Abstract

In this letter, we provide experimental evidence of the time-reversal symmetric Hall effect in a mesoscopic system, namely high-mobility graphene/WSe$_2$ heterostructures. This linear, dissipative Hall effect, whose sign depends on the sign of the charge carriers, persists up to room temperature. The magnitude and the sign of the Hall signal can be tuned using an external perpendicular electric field. Our joint experimental and theoretical study establishes that the strain induced by lattice mismatch, or angle inhomogeneity, produces anisotropic bands in graphene while simultaneously breaking the inversion symmetry. The band anisotropy and reduced spatial symmetry lead to the appearance of a time-reversal symmetric Hall effect. Our study establishes graphene-transition metal dichalcogenide-based heterostructures as an excellent platform for studying the effects of broken symmetry on the physical properties of band-engineered two-dimensional systems.