Probing a Proximity-Coupling-Induced Hybrid Anomalous Hall Effect in Epitaxial MnBi₂Te₄/Bi₂Te₃ Nanostructures

Abstract

The alliance of magnetism and non-trivial topology provides a promising platform for exploring exotic topological quantum states such as high temperature quantum anomalous Hall insulator and robust axion insulator, and the strategies of dilute magnetically doped, intrinsic magnetic materials and proximity of magnetic materials have been successfully pursued to achieve magnetic ordering in topological insulators. However, the intricate interplay between the topological insulator and intrinsic magnetic topological insulator has rarely been investigated, which may hold the promise of producing quantum anomalous Hall insulators with a tunable Chern number. Here, we grow MnBi2Te4/Bi2Te3 nanostructures by means of a molecular beam epitaxy and observe a typical proximity-coupling-induced anomalous Hall effect at the interface. The long-range ferromagnetic order with perpendicular magnetic anisotropy in the Bi2Te3 layer has been established successfully. The hybrid anomalous Hall effect from both layers can be separated precisely by the classical molecular field model in the whole magnetic field regime, which reflects that the magnetization of heterostructures reversed layer by layer gradually. Moreover, through an ionic gate, we can partly modulate the hybrid anomalous Hall effect of heterostructures, and the Fermi level-associated anomalous Hall effect component can be tailored effectively. Our work not only realizes the introduction of magnetic order to a topological material but also verifies a strategy to modulate the anomalous Hall effect response via structural engineering. These findings may spark further exploration of multiple quantum anomalous Hall insulators and heterostructure-based multifunctional applications.

Exploring the Epitaxial Growth Kinetics and Anomalous Hall Effect in Magnetic Topological Insulator MnBi2Te4 Films

“…Recently, the molecular beam epitaxy (MBE) technique was successfully utilized to grow MBT-based thin films to investigate their intriguing topological quantum phenomena. ,,− Two growth recipes were applied for fabricating MBT-based thin films, including the alternating deposition of Bi 2 Te 3 and MnTe layers followed by in situ annealing, and the coevaporation of Mn, Bi, and Te elements combined with the delicate adjustment of the Mn/Bi flux ratio. ,, Angle-resolved photoemission spectroscopy (ARPES) measurements revealed linearly dispersed TSS, and magnetic and magneto-transport characterizations depicted anomalous hysteresis loops in MBT-based thin films, ,, verifying their inherent MTI features. Chang et al reported that their MBT films contain a Mn-doped Bi 2 Te 3 impurity by examining the nonsquare anomalous Hall (AH) hysteresis loops.…”