Even–Odd Layer-Dependent Anomalous Hall Effect in Topological Magnet MnBi2Te4Thin Films

Recently, MnBi2Te4has been demonstrated to be an intrinsic magnetic topological insulator and the quantum anomalous Hall (QAH) effect was observed in exfoliated MnBi2Te4flakes. Here, we used molecular beam epitaxy (MBE) to grow MnBi2Te4films with thickness down to 1 septuple layer (SL) and performed thickness-dependent transport measurements. We observed a nonsquare hysteresis loop in the antiferromagnetic state for films with thickness greater than 2 SL. The hysteresis loop can be separated into two AH components. We demonstrated that one AH component with the larger coercive field is from the dominant MnBi2Te4phase, whereas the other AH component with the smaller coercive field is from the minor Mn-doped Bi2Te3phase. The extracted AH component of the MnBi2Te4phase shows a clear even–odd layer-dependent behavior. Our studies reveal insights on how to optimize the MBE growth conditions to improve the quality of MnBi2Te4films.