Figure 1.

Gate-dependent transport properties of the 10-SL MnBi₂Te₄ device s6. (a) Crystal structure of MnBi₂Te₄. The red and blue arrows denote magnetic moment directions of Mn ions. (b) Optical image of the 10-SL MnBi₂Te₄ device s6. Scale bar represents 10 μm. (c) Temperature dependence of R_xx at V_bg = 0 V. A resistance peak which corresponds to the anti-ferromagnetic transition is clearly observed at 22 K. (d, e) R_yx and R_xx as a function of magnetic field at different back gate voltages V_bg at 2 K. Under applied magnetic field, the Hall resistance plateau with a value of h/2e² and vanishing R_xx are detected at −10 V≤ V_bg ≤ −58 V, which are characteristics of quantized Hall effect with Chern number C = 2. The black and red traces represent magnetic field sweeping to the positive and negative directions, respectively. (f) R_xx and R_yx as a function of V_bg at 2 K and −15 T. (g) The schematic FM order and electronic structure of the C = 2 Chern insulator state with two chiral edge states across the band gap. The grey and green colors are used to distinguish the adjacent MnBi₂Te₄ SLs.