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

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.

19 pages, 4 figures