Epitaxial growth of topological insulator $\beta$-Ag2Te thin films

TL;DR

This paper demonstrates the successful epitaxial growth of $eta$-Ag2Te thin films, a topological insulator, using molecular beam epitaxy, and characterizes their structural and electrical properties.

Contribution

It reports the first epitaxial growth of $eta$-Ag2Te thin films and confirms their crystal orientation and surface conduction properties.

Findings

Epitaxial $eta$-Ag2Te films exhibit (002) orientation.

Films show two-dimensional metallic surface conduction.

Bulk remains insulating, enabling surface state studies.

Abstract

We report epitaxial growth of $\beta$-Ag2Te thin films by molecular beam epitaxy. $\beta$-Ag2Te, recently identified as a topological insulator, was grown by depositing Ag on InP substrate at room temperature followed by Te supply at elevated temperature. X-ray diffraction measurements and transmission electron microscopy analyses confirmed the (002) crystal orientation and the epitaxial atomic arrangement of $\beta$-Ag2Te thin films. Electrical transport measurements revealed that the $\beta$-Ag2Te thin film exhibits two-dimensional metallic conduction while the bulk remains insulating. The epitaxial $\beta$-Ag2Te thin films obtained here provide a viable platform for investigating emergent phenomena arising from surface Dirac states and for designing heterojunction-based device structures.