Planar Hall effect induced by anisotropic orbital magnetoresistance in type-II Dirac semimetal PdTe2

Abstract

We measure planar Hall effect (PHE) and longitudinal anisotropic magnetoresistance (AMR) with a magnetic field rotating in the a-b plane in the type-II Dirac semimetal PdTe2. The measured PHE and AMR curves can be fitted by the theoretical equations; however, a detailed analysis of the extracted data demonstrates that the parameter related to PHE and AMR has no relationship with the chiral anomaly due to the absence of negative longitudinal magnetoresistance (MR) when the electric and magnetic fields are parallel to each other. Meanwhile, we prove that the origin of PHE in PdTe2 is the anisotropic orbital MR. Our work suggests that negative longitudinal MR is necessary to identify chiral anomaly, and we cannot in general use PHE as a signal for the presence of the chiral anomaly in Dirac/Weyl semimetals.