Interfacing topological insulators and ferrimagnets: Bi$_2$Te$_3$ and Fe$_3$O$_4$ heterostructures grown by molecular beam epitaxy

TL;DR

This study investigates Bi$_2$Te$_3$/Fe$_3$O$_4$ heterostructures grown by molecular beam epitaxy, revealing that Bi$_2$Te$_3$ on Fe$_3$O$_4$ exhibits promising properties for realizing the quantum anomalous Hall effect.

Contribution

It compares two heterostructure configurations and identifies Bi$_2$Te$_3$ on Fe$_3$O$_4$ as more chemically stable and electronically suitable for topological applications.

Findings

Bi$_2$Te$_3$ on Fe$_3$O$_4$ shows better chemical stability.

Transport measurements suggest a gap opening in topological surface states.

The heterostructure is promising for quantum anomalous Hall effect studies.

Abstract

Relying on the magnetism induced by the proximity effect in heterostructures of topological insulators and magnetic insulators is one of the promising routes to achieve the quantum anomalous Hall effect. Here we investigate heterostructures of Bi$_2$Te$_3$ and Fe$_3$O$_4$. By growing two different types of heterostructures by molecular beam epitaxy, Fe$_3$O$_4$ on Bi$_2$Te$_3$ and Bi$_2$Te$_3$ on Fe$_3$O$_4$, we explore differences in chemical stability, crystalline quality, electronic structure, and transport properties. We find the heterostructure Bi$_2$Te$_3$ on Fe$_3$O$_4$ to be a more viable approach, with transport signatures in agreement with a gap opening in the topological surface states.