Observation of planar Hall effect in quasi-two-dimensional topological insulator candidate Ni3Bi2Se2

Abstract

The observation of the Planar Hall Effect (PHE) sheds light on the spin textures and topological characteristics of materials, indicating potential applications in quantum computing and electronic devices. However, in bulk single crystals of topological insulators (TIs), where the chiral anomaly is absent and the contribution of topological surface states can be overlooked, the origin of PHE remains elusive. Here, we have obtained high-quality single crystals of Ni3Bi2Se2 and systematically investigated their magneto-electric transport properties. The ordinary Hall resistivity reveals the simultaneous presence of electrons and holes. A novel π-period PHE, which depends on the relative angle with the driving electric and magnetic fields, has been observed, indicating the breaking of mirror reflection symmetry. The angular dependence of in-plane anisotropic magnetoresistance and the field-dependent PHE signal underscore the critical role of anisotropic orbital magnetoresistance. Our findings offer a new platform for deepening our understanding of the PHE and its underlying mechanisms in TIs.