Record-High Proximity-Induced Anomalous Hall Effect in (Bi$_x$Sb$_{1-x}$)2Te$_3$ Thin Film Grown on CrGeTe$_3$ Substrate

TL;DR

This study demonstrates that growing (Bi_xSb_{1-x})_2Te_3 thin films on well-matched CeGeTe_3 substrates significantly enhances the proximity-induced anomalous Hall effect, surpassing previous limitations caused by interfacial disorder.

Contribution

It reveals that structural and chemical matching at the interface greatly improves the proximity-induced anomalous Hall resistance in TI heterostructures.

Findings

Proximity-induced anomalous Hall resistance increased by over an order of magnitude.

Well-matched substrates reduce interfacial disorder, enhancing magnetic proximity effects.

The approach offers a pathway to higher-temperature quantum anomalous Hall effects.

Abstract

Quantum anomalous Hall effect(QAHE) can only be realized at extremely low temperatures in magnetically doped topological insulators(TIs) due to limitations inherent with the doping precess. In an effort to boost the quantization temperature of QAHE, magnetic proximity effect in magnetic insulator/TI heterostructures has been extensively investigated. However, the observed anomalous Hall resistance has never been more than several Ohms, presumably owing to the interfacial disorders caused by the structural and chemical mismatch. Here, we show that, by growing (BixSb1-x)2Te3(BST) thin films on structurally and chemically well-matched, ferromagnetic-insulating CeGeTe3(CGT) substrates, the proximity-induced anomalous Hall resistance can be enhanced by more than an order of magnitude. This sheds light on the importance of structural and chemical match for magnetic insulator/TI proximity systems.