Giant Planar Hall Effect in the Dirac Semimetal ZrTe5

TL;DR

This paper reports the observation of a giant planar Hall effect in ZrTe5 nanoplates, confirming its status as a Dirac semimetal through various magnetotransport phenomena and their dependence on sample thickness.

Contribution

It provides experimental evidence of the giant planar Hall effect and related topological features in ZrTe5, clarifying its classification as a Dirac semimetal.

Findings

Giant planar Hall resistivity with two magnetic-field dependences

Maximum Hall resistivity at the Lifshitz transition temperature

Observation of nontrivial Berry phase and negative magnetoresistance

Abstract

Recently, giant planar Hall effect originating from chiral anomaly has been predicted in nonmagnetic Dirac/Weyl semimetals. ZrTe5 is considered to be an intriguing Dirac semimetal at the boundary of weak topological insulators and strong topological insulators, though this claim still remains controversial. Here, we report the observation in ZrTe5 of the giant planar Hall resistivity that shows two different magnetic-field dependences as predicted by theory and a maximum at the Lifshitz transition temperature. We found that the giant planar Hall resistivity fades out with decreasing the thickness of ZrTe5 nanoplates, which may be ascribed to the vanishing of the 3D nature of the samples. In addition, we have observed a nontrivial Berry phase, chiral-anomaly-induced negative longitudinal magnetoresistance, and a giant in-plane anisotropic magnetoresistance in these ZrTe5 nanoplates. All the experimental observations demonstrated coherently that ZrTe5 is a Dirac semimetal.