Strain in Epitaxial High-Index Bi2Se3(221) Films Grown by Molecular-Beam Epitaxy

TL;DR

This study investigates the growth and strain relaxation dynamics of high-index Bi2Se3(221) films on In2Se3-buffered GaAs(001), revealing slow strain relaxation due to layered crystal structure and strong interfacial chemical bonding, with implications for topological insulator manipulation.

Contribution

It demonstrates the epitaxial growth of high-index Bi2Se3(221) films with slow strain relaxation and analyzes interfacial bonding using first-principles calculations, advancing topological insulator engineering.

Findings

Slow strain relaxation in Bi2Se3(221) films due to layered structure.

Strong chemical bonding at Bi2Se3/In2Se3 interface.

Feasibility of strain engineering in topological insulators.

Abstract

High-index Bi2Se3(221) film has been grown on In2Se3-buffered GaAs(001), in which a much retarded strain relaxation dynamics is recorded. The slow strain-relaxation process of in epitaxial Bi2Se3(221) can be attributed to the layered structure of Bi2Se3 crystal, where the epifilm grown along [221] is like a pile of weakly-coupled quintuple layer slabs stacked side-by-side on substrate. Finally, we have revealed the strong chemical bonding at the interface of Bi2Se3 and In2Se3 by plotting differential charge contour calculated by first-principle method. This study points to the feasibility of achieving strained TIs for manipulating the properties of topological systems.