Doping tuned anomalous Hall effect in the van der Waals magnetic topological phases Mn(Sb1 − x Bi x )4Te7

Abstract

The van der Waals (vdW) MnSb4Te7 is a newly synthesized antiferromagnetic (AFM) topological insulator hosting a robust axion insulator state irrelative to the specific spin structure. However, the intrinsic hole doped character of MnSb4Te7 makes the Fermi level far away from the Dirac point of about 180 meV, which is unfavorable for the exploration of exotic topological properties such as the quantum anomalous Hall effect (QAHE). To shift up the Fermi level close to the Dirac point, the strategy of partially replacing Sb with Bi as Mn(Sb1−x Bi x )4Te7 was tried and the magnetotransport properties, in particular, the anomalous Hall effect, were measured and analyzed. Through the electron doping, the anomalous Hall conductance σ AH changes from negative to positive between x = 0.3 and 0.5, indicative of a possible topological transition. Besides, a charge neutrality point (CNP) also appears between x = 0.6 and 0.7. The results would be instructive for further understanding the interplay between nontrivial topological states and the magnetism, as well as for the exploration of exotic topological properties.