  The van der Waals antiferromagnetic topological insulator MnBi2Te4 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 MnBi2Te4 in the ground state. In this article, we demonstrate that
fabrication can induce mismatched even-odd layer dependent magnetotransport in
few-layer MnBi2Te4. We perform a comprehensive study of the magnetotransport
properties in 6- and 7-septuple-layer MnBi2Te4, 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 MnBi2Te4 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
MnBi2Te4, but also highlights the critical issues concerning the fabrication
and characterization of 2D material devices.
