Chirality-tunable non-linear Hall effect

TL;DR

This paper explores how chiral materials can exhibit and tune the non-linear Hall effect through Berry curvature dipoles, using first-principles calculations and models, highlighting their potential for novel electronic phenomena.

Contribution

It demonstrates that chiral materials inherently support and can control Berry curvature dipoles, leading to tunable non-linear Hall effects, and provides computational evidence across various material classes.

Findings

Chiral materials show opposite Berry curvature dipoles for enantiomers.

Berry curvature dipole magnitude can be tuned in chiral systems.

Predicted non-linear Hall voltages are experimentally accessible.

Abstract

The non-linear generalization of the Hall effect has recently gained much attention, with a rapidly growing list of non-centrosymmetric materials that display higher-order Hall responses under time-reversal invariant conditions. The intrinsic second-order Hall response arises due to the first-order moment of Berry curvature -- termed Berry curvature dipole -- which requires broken inversion and low crystal symmetries. Chiral materials are characterized by their lack of improper symmetries such as inversion, mirror plane, and roto-inversion. Owing to this absence of symmetries, in this work, we propose chiral systems as ideal platforms to study the Berry curvature dipole-induced non-linear Hall effects. We use state-of-the-art first-principles computations, in conjunction with symmetry analyses, to explore a variety of chiral material classes -- metallic \ch{NbSi2}, semiconducting elemental Te, insulating HgS, and topological multifold semimetal CoSi. We present the emergence and tunability of the Berry curvature dipole in these chiral materials. In particular, we demonstrate that the two enantiomeric pairs exhibit an exactly opposite sign of the Berry curvature dipole. We complement our \textit{ab initio} findings with a general tight-binding minimal model and give estimates for non-linear Hall voltages, which are experimentally accessible. Our predictions put forward chiral materials as an emerging class of materials to realize non-linear Hall phenomena and highlight an as-yet-unexplored aspect of these systems.