AlO<italic>x</italic>/LiF composite protection layer for Cr-doped (Bi,Sb)2Te3 quantum anomalous Hall films

AlO_x/LiF composite protection layer for Cr-doped (Bi,Sb)₂Te₃ quantum anomalous Hall films

Ou Yunbo¹, Feng Yang², Feng Xiao^{1, 2}, Hao Zhenqi², Zhang Liguo², Liu Chang², Wang Yayu^{2, †,}, He Ke^{2, ‡,}, Ma Xucun², Xue Qikun²

Magnetic field dependence of (a) ρ_yx and (b) ρ_xx for bare (green lines) and 40-nm LiF-capped (blue lines) 5-QL Cr_0.15(Bi_0.1Sb_0.9)_1.85Te₃ films with gate voltage of −1 V, 36 V. (c) V_g dependence of ρ_yx at zero magnetic field for bare (green line) and 40-nm LiF-capped (blue line) 5-QL Cr_0.15(Bi_0.1Sb_0.9)_1.85Te₃ films. Magnetic field dependence of ρ_yx and ρ_xx (V_g = 200 V), V_g dependence of ρ_yx at zero magnetic field of 40-nm LiF-capped 5-QL Cr_0.15(Bi_0.1Sb_0.9)_1.85Te₃ films, which is kept in argon glove box for 60 days, are shown with red lines in panels (a), (b), and (c). All the measurements are conducted at 1.5 K.