Effects of GaAs buffer layer on quantum anomalous Hall insulator Vy(BixSb1-x)2-yTe3

TL;DR

This study demonstrates that using a GaAs buffer layer improves the structural quality of VBST quantum anomalous Hall insulators, leading to enhanced magnetic properties while maintaining similar QAHE stability.

Contribution

It introduces the use of a GaAs buffer layer for growing VBST, showing improved crystal quality and larger coercive fields compared to direct growth on InP.

Findings

GaAs buffer layer enhances crystal and interface quality.

QAHE observed in both samples with similar thermal stability.

Sample on GaAs exhibits nearly double coercive field.

Abstract

We report the growth, structural characterization, and transport properties of the quantum anomalous Hall insulator Vy(BixSb1-x)2-yTe3 (VBST) grown on a GaAs buffer layer by molecular beam epitaxy on a GaAs(111)A substrate. X-ray diffraction and transmission electron microscopy show that the implementation of a GaAs buffer layer improves the crystal and interface quality compared to the control sample grown directly on an InP substrate. Both samples exhibit the quantum anomalous Hall effect (QAHE), but with similar thermal stability despite the different structural properties. Notably, the QAHE in the sample grown on a GaAs buffer layer displays a significantly larger (almost double) coercive field with a much smaller resistivity peak at the magnetization reversal. Possible effects of the interface quality on the magnetic properties of VBST and the QAHE are discussed.