Geometrical Nonlinear Hall Effect Induced by Lorentz Force

TL;DR

This paper introduces a new geometrical nonlinear Hall effect (type-III) induced by Lorentz force and anomalous velocity, prominent near band crossings, with potential applications in electronic devices like transistors.

Contribution

It proposes a novel type-III nonlinear Hall effect driven by Berry curvature structures, supported by theoretical and first-principles analysis, expanding the understanding of nonlinear Hall phenomena.

Findings

Type-III NLH effect is prominent near band crossings.

Giant unidirectional magnetoresistance observed in strained MnBi2Te4.

Unique symmetry properties linked to Berry curvature square dipole.

Abstract

The recently discovered nonlinear Hall (NLH) effect arises either without external magnetic field (type-I) or with an in-plane magnetic field (type-II). In this work we propose a new type of geometrical nonlinear Hall effect with an out-of-plane magnetic field (type-III) induced by the combination of Lorentz force and anomalous electronic velocity. The type-III NLH effect is proportional to the more refined structures of Bloch wave functions, i.e., the dipole moment of square of Berry curvature, thus becoming prominent near the band crossings or anticrossings. Our effective model analysis and first-principles calculations show that gate-tuned MnBi$_2$Te$_4$ thin film under uniaxial strain is an ideal platform to observe this effect. Especially, giant unidirectional magnetoresistance can occur in this material, based on which an efficient electrical transistor device prototype can be built. Finally a symmetry analysis indicates that type-III NLH effect has unique symmetry properties stemming from Berry curvature square dipole, which is different from other previously reported NLH effects and can exist in a wider class of magnetic crystals. Our study offers new paradigms for nonlinear electronics.