Non-topological Origin of the Planar Hall Effect in Type-II Dirac Semimetal NiTe2

TL;DR

This study shows that the planar Hall effect observed in NiTe2, a type-II Dirac semimetal, originates from trivial orbital magnetoresistance rather than chiral anomaly, challenging previous assumptions about PHE as a topological indicator.

Contribution

It demonstrates that PHE in NiTe2 is due to non-topological effects, emphasizing the need to distinguish trivial contributions from topological phenomena in such materials.

Findings

PHE observed in NiTe2 at low temperatures.

PHE arises from trivial orbital magnetoresistance.

PHE is not exclusively indicative of chiral anomaly.

Abstract

Dirac and Weyl semimetals are new discovered topological nontrivial materials with the linear band dispersions around the Dirac/Weyl points. When applying non-orthogonal electric current and magnetic field, an exotic phenomenon called chiral anomaly arises and negative longitudinal resistance can be detected. Recently, a new phenomenon named planer Hall effect (PHE) is considered to be another indication of chiral anomaly which has been observed in many topological semimetals. However, it still remains a question that is the PHE only attributed to chiral anomaly? Here we demonstrate the PHE in a new-discovered type-II Dirac semimetal NiTe2 by low temperature transport. However, after detailed analysis, we conclude that the PHE results from the trivial orbital magnetoresistance. This work reveals that PHE is not a sufficient condition of chiral anomaly and one need to take special care of other non-topological contribution in such studies.