Chiral-anomaly induced large negative magnetoresistance and nontrivial π-Berry phase in half-Heusler compounds RPtBi (R=Tb, Ho, and Er)
Jie Chen, Hang Li, Bei Ding, Enke Liu, Yuan Yao, Guangheng Wu, Wenhong Wang
Abstract
We report on the observation of a large negative magnetoresistance (MR) with magnitudes of −67%, −45%, and −31% in antiferromagnetic half-Heusler compounds TbPtBi, HoPtBi, and ErPtBi, respectively. It is found that with increasing temperature, the values of the negative MR vary smoothly and persist well above their Neel temperature TN. Besides the negative MR effects, we have further observed a nontrivial Berry phase (∼π) extracted from Shubnikov–de Haas oscillation in HoPtBi. These results together with band structure calculations unambiguously give evidence of the chiral anomaly effect and are valuable for understanding the Weyl fermions in magnetic lanthanide half-Heusler compounds.