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Enormous Berry-Curvature-Based Anomalous Hall Effect in Topological Insulator (Bi, Sb)2Te3 on FErrimagnetic Europium Iron Garnet beyond 400 K
W.-J. Zou, M.-X. Guo, J.-F. Wong, Z.-P. Huang, J.-M. Chia, W.-N. Chen, S.-X. Wang, K.-Y. Lin, L. B. Young, Y.-H. G. Lin, M. Yahyavi, C.-T. Wu, H.-T. Jeng, S.-F. Lee, T.-R. Chang,* M. Hong,* and J. Kwo*
To realize the quantum anomalous Hall effect (QAHE) at elevated temperatures, the approach of magnetic proximity effect (MPE) was adopted to break the time-reversal symmetry in the topological insulator (Bi0.3Sb0.7)2Te3 (BST) based heterostructures with a ferrimagnetic insulator europium iron garnet (EuIG) of perpendicular magnetic anisotropy. Here we demonstrate large anomalous Hall resistance (RAHE) exceeding 8 Ω (ρAHE of 3.2 μΩ·cm) at 300 K and sustaining to 400 K in 35 BST/EuIG samples, surpassing the past record of 0.28 Ω (ρAHE of 0.14 μΩ·cm) at 300 K. The large RAHE is attributed to an atomically abrupt, Fe-rich interface between BST and EuIG. Importantly, the gate dependence of the AHE loops shows no sign change with varying chemical potential. This observation is supported by our first-principles calculations via applying a gradient Zeeman field plus a contact potential on BST. Our calculations further demonstrate that the AHE in this heterostructure is attributed to the intrinsic Berry curvature. Furthermore, for gate-biased 4 nm BST on EuIG, a pronounced topological Hall effect-like (THE-like) feature coexisting with AHE is observed at the negative top-gate voltage up to 15 K. Interface tuning with theoretical calculations has realized topologically distinct phenomena in tailored magnetic TI-based heterostructures.