Anisotropic magnetoresistance and the field-induced anomalous valley inversion in half-Heusler TbPtBi

We have performed detailed magnetic and anisotropic magnetoresistance (AMR) measurements on a magnetic-field-induced topological Weyl semimetal, TbPtBi, exhibiting a weak metamagnetic transition in the antiferromagnetic state. The magnetic torque and temperature-dependent AMR measurements indicate that the spin order dominates the symmetry of AMR curves at temperature below Neel temperature (T-N) and low magnetic fields. Remarkably, the AMR with a twofold symmetry gradually dominates the curves as the magnetic fields increase. Moreover, sign change in the AMR effect is confirmed for both T < T-N and T > T-N at high magnetic fields, which may be related to the magnetic field-induced splitting of the topological band in TbPtBi.