Fabrication-induced even-odd discrepancy of magnetotransport in few-layer MnBiTe.

The van der Waals antiferromagnetic topological insulator MnBiTe represents a promising platform for exploring the layer-dependent magnetism and topological states of matter. Recently observed discrepancies between magnetic and transport properties have aroused controversies concerning the topological nature of MnBiTe in the ground state. In this article, we demonstrate that fabrication can induce mismatched even-odd layer dependent magnetotransport in few-layer MnBiTe. We perform a comprehensive study of the magnetotransport properties in 6- and 7-septuple-layer MnBiTe, and reveal that both even- and odd-number-layer device can show zero Hall plateau phenomena in zero magnetic field. Importantly, a statistical survey of the optical contrast in more than 200 MnBiTe flakes reveals that the zero Hall plateau in odd-number-layer devices arises from the reduction of the effective thickness during the fabrication, a factor that was rarely noticed in previous studies of 2D materials. Our finding not only provides an explanation to the controversies regarding the discrepancy of the even-odd layer dependent magnetotransport in MnBiTe, but also highlights the critical issues concerning the fabrication and characterization of 2D material devices.