Magnus Hall effect in three-dimensional topological semimetals

TL;DR

This paper investigates the Magnus Hall effect in three-dimensional topological semimetals, analyzing how features like tilt, anisotropy, and degeneracy influence the effect, with implications for experimental transport measurements.

Contribution

It demonstrates the possibility of finite Magnus Hall effect in 3D semimetals without time-reversal symmetry and explores the impact of various bandstructure features on the effect.

Findings

Finite MHE response possible without TRS if inversion symmetry is broken.

Tilt of the node significantly affects transport coefficients.

Anisotropic dispersions lead to direction-dependent MHE features.

Abstract

Magnus Hall effect (MHE) is a non-linear Hall effect requiring no external magnetic field, which can be observed when an in-built electric field couples to the Berry curvature of the bandstructure, producing a current in the transverse direction. In this paper, we explore MHE in the context of various three-dimensional semimetals, incorporating various features like tilt, anisotropy, and multi-fold degeneracy. We numerically calculate the Magnus Hall conductivity tensors and transport coefficients, within the framework of the Boltzmann transport theory. Although MHE was originally predicted for two-dimensional materials with time-reversal symmetry (TRS), we show that a finite MHE response is possible in materials without TRS. If TRS is preserved, broken inversion symmetry is needed to prevent the cancellation of the MHE contributions while summing over the Brillouin zone. The amount of tilt of the node of a semimetal greatly affects the transport coefficients. In presence of anisotropic dispersions, we find that the MHE features differ depending on the directions of measurements (as expected). To demonstrate these dependencies, our investigations include Weyl, multi-Weyl, multi-fold, and nodal-line semimetals. Our analysis is of great importance for transport measurements in experiments involving non-linear Hall effects.