Observation of planar Hall effect in Type-II Dirac semimetal PtTe$_{2}$

TL;DR

This study reports the first experimental observation of the Planar Hall effect in the nonmagnetic Type-II Dirac semimetal PtTe$_{2}$, demonstrating its robustness up to near room temperature and its potential as a diagnostic for topological properties.

Contribution

The paper provides the first experimental evidence of PHE in PtTe$_{2}$, a nonmagnetic Dirac semimetal, highlighting its intrinsic nature and relevance for topological diagnostics.

Findings

PHE observed in PtTe$_{2}$ up to near room temperature.

PHE is an intrinsic effect related to Berry curvature.

PHE can serve as a diagnostic for topological character even with Dirac nodes away from Fermi level.

Abstract

We report experimental observation of the Planar Hall effect (PHE) in a type-II Dirac semimetal PtTe$_2$. This unusual Hall effect is not expected in nonmagnetc materials such as PtTe$_2$, and has been observed previously mostly in magnetic semiconductors or metals. Remarkably, the PHE in PtTe$_2$ can be observed up to temperatures near room temperature which indicates the robustness of the effect. This is in contrast to the chiral anomaly induced negative longitudnal magnetoresistance (LMR), which can be observed only in the low temperature regime and is sensitive to extrinsic effects, such as current jetting and chemical inhomogeneities in crystals of high mobility. Planar Hall effect on the other hand is a purely intrinsic effect generated by the Berry curvature in Weyl semimetals. Additionally, the PHE is observed for PtTe$_2$ even though the Dirac node is $\approx 0.8$~eV away from the Fermi level. Thus our results strongly indicate that PHE can be used as a crucial transport diagnostic for topological character even for band structures with Dirac nodes slightly away from the Fermi energy.