Large anomalous Hall effect in ferromagnetic insulator-topological insulator heterostructures

TL;DR

This paper reports the successful fabrication of Bi2Te3/Cr2Ge2Te6 heterostructures exhibiting a large anomalous Hall effect at low temperatures, highlighting potential for spintronic applications.

Contribution

It demonstrates van der Waals epitaxy of topological insulator on ferromagnetic insulator with a sharp interface and characterizes the resulting anomalous Hall effect.

Findings

Large anomalous Hall effect observed at low temperatures

Easy axis of magnetization aligned along the c-axis

Curie temperature of 61 K in the heterostructure

Abstract

We demonstrate the van der Waals epitaxy of the topological insulator compound Bi2Te3 on the ferromagnetic insulator Cr2Ge2Te6. The layers are oriented with (001) of Bi2Te3 parallel to (001) of Cr2Ge2Te6 and (110) of Bi2Te3 parallel to (100) of Cr2Ge2Te6. Cross-sectional transmission electron microscopy indicates the formation of a sharp interface. At low temperatures, bilayers consisting of Bi2Te3 on Cr2Ge2Te6 exhibit a large anomalous Hall effect (AHE). Tilted field studies of the AHE indicate that the easy axis lies along the c-axis of the heterostructure, consistent with magnetization measurements in bulk Cr2Ge2Te6. The 61 K Curie temperature of Cr2Ge2Te6 and the use of near-stoichiometric materials may lead to the development of spintronic devices based on the AHE.