Generic Chiral Anomaly and Planar Hall Effect in a Non-Weyl System

TL;DR

This paper demonstrates that chiral anomaly effects, including negative longitudinal magnetoresistance and planar Hall effect, occur in a non-Weyl nodal-line semimetal ZrTe$_5$, expanding the understanding of anomaly-related phenomena beyond Weyl systems.

Contribution

It reveals that chiral anomaly physics applies to non-Weyl nodal-line semimetals like ZrTe$_5$, explaining magnetotransport features without Weyl points.

Findings

Negative longitudinal magnetoresistance observed in ZrTe$_5$

Gigantic planar Hall effect with unusual magnetic-field dependence

Chiral anomaly effects extend beyond Weyl systems to nodal-line semimetals

Abstract

The condensed-matter version of the chiral anomaly describes how electrons are pumped from a Weyl node with negative chirality to a Weyl node with positive chirality using parallel electric and magnetic fields. Key experimental signatures are a negative longitudinal magnetoresistance (LMR) and the planar Hall effect (PHE), both of which have been experimentally observed. Here, we show that the chiral anomaly explains key features of magnetotransport in the nodal-line semimetal ZrTe$_5$ despite the absence of Weyl points. The anomaly physics applies generically to materials in the quantum limit, when electron transport becomes quasi-one-dimensional, provided that Fermi velocities remain sufficiently large. This explains not only the negative LMR but also the PHE with a gigantic Hall angle and a highly unusual magnetic-field-angle dependence in ZrTe$_5$.