The interplay of non-trivial band topology and magnetism in Half-Heusler alloys (Tb/Dy)PtBi

Half-Heusler compound GdPtBi is one of the few time reversal symmetry breaking Weyl semimetals induced by magnetic field and is characterized by the chiral anomaly and the anomalous Hall effect with an exceptionally large Hall angle θ_H (≈0.2)[1-3]. In order to understand how the Weyl bands interplay with magnetism in Half-Heusler alloys, we have studied magnetotransport properties of (Tb/Dy)PtBi. We observed anomalous Hall effects in both materials and find their Hall angles as well as magnetoresistance sensitively depend on their magnetic states. In TbPtBi, its θ_H is found to be 0.4, twice that of GdPtBi and its magnetoresistance shows signatures of chiral anomaly. However, for DyPtBi, although Dy carries magnetic moment greater than those of Gd and Tb, it does not show chiral anomaly and its θ_H is much smaller. There discrepancies can be attributed to the different magnetic states of these two materials. These findings suggest that the non-trivial band topology under magnetic field of half-Heusler alloys is intimately associated the magnetism generated by rare earth element.

[1] T. Suzuki et al., Nat. Phys. (2016).
[2] M. Hirschberger et al., Nat. Mater. 15, 1161 (2016).
[3] C. Shekhar et al., ArXiv Prepr. ArXiv160401641 (2016).