Planar Hall Effect in Quasi-Two-Dimensional Materials

TL;DR

This paper reports the discovery of a unique 2D planar Hall effect in quasi-2D materials, driven by hidden Berry curvature components, with potential for novel electronic applications.

Contribution

It introduces the concept of a 2D planar Hall effect originating from hidden Berry curvature and orbital magnetic moments in quasi-2D materials, expanding understanding of band geometry effects.

Findings

Identification of all planar band geometric contributions to 2DPHE

Demonstration of 2DPHE sensitivity to Lifshitz transitions in bilayer graphene

Classification of crystalline symmetry restrictions on 2DPHE

Abstract

The planar Hall effect in 3D systems is an effective probe for their Berry curvature, topology, and electronic properties. However, the Berry curvature-induced conventional planar Hall effect is forbidden in 2D systems as the out-of-plane Berry curvature cannot couple to the band velocity of the electrons moving in the 2D plane. Here, we demonstrate a unique 2D planar Hall effect (2DPHE) originating from the hidden planar components of the Berry curvature and orbital magnetic moment in quasi-2D materials. We identify all planar band geometric contributions to 2DPHE and classify their crystalline symmetry restrictions. Using gated bilayer graphene as an example, we show that in addition to capturing the hidden band geometric effects, 2DPHE is also sensitive to the Lifshitz transitions. Our work motivates further exploration of hidden planar band geometry-induced 2DPHE and related transport phenomena for innovative applications.