Zero-field chiral edge transport in an intrinsic magnetic topological insulator MnBi2Te4

The Dissipationless chiral edge state (CES) stands as a pivotal feature in quantum anomalous Hall (QAH) insulators. The dissipationless nature and chirality give rise to unique transport properties and provide insights into future electronics and spintronics. In recent years, a new van der Waals intrinsic magnetic topological insulator, MnBi2Te4 (MBT), has attracted significant research interests. The quantum anomalous Hall effect has been successfully achieved in odd-layer MBT. However, few studies can reproduce the zero-field quantization due to poor sample quality, and as a result, the transport properties of CES have rarely been explored in a well quantized MBT sample at zero magnetic field. Here, we report an electrical transport study of CES in a 5-septuple layer (SL) MBT sample, in which zero-field quantization is successfully achieved. The four-terminal and three-terminal measurements provide unambiguous evidence for the presence of zero-field CES in the sample. The nonreciprocal resistance transport demonstrates the dominance of CES at charge neutrality point, as well as the strong interplay between CES and bulk conduction channels at band edge. Our research enriches the fundamental understanding of chiral edge states in MBT and paves the way for future dissipationless electronics applications.