Anisotropic transverse magnetoresistance temperature dependence in Mn3Ga Weyl semimetal with chiral anomaly

Abstract

Hexagonal antiferromagnetic D019-Mn3X (X = Sn, Ge, Ga) compounds, with a non-collinear Kagome spin structure, are Weyl semimetals exhibiting novel topological transport properties. The longitudinal magnetoresistance of c-oriented epitaxial Ru/Mn3Ga thin films exhibits a positive quadratic dependence on magnetic field over a wide range of temperatures. Here we describe the transverse magnetoresistance, with the field in the out-of-plane direction, for c-oriented epitaxial GaN (0001)/Mn3Ga films. There is a transition from a negative linear to a positive quadratic dependence on magnetic field in the temperature range from 200 K to 300 K. The electrical resistivity shows a metallic to semiconductor transition at 230 K. By applying the electric field along two perpendicular in-plane directions we find asymmetry in the magnetoresistance curves due to self-spin polarized currents created through magnetic octupole clusters. First principles calculations confirmed the metallic to semiconductor transition corresponds to reordering the spin structure to a higher symmetry configuration.