Synthesis of layered gold tellurides AuSbTe and Au$_2$Te$_3$ and their semiconducting and metallic behavior

TL;DR

This study synthesizes layered gold tellurides AuSbTe and Au$_{1.9}$Sb$_{0.46}$Te$_{2.64}$, revealing their melting behaviors, electronic properties, and synthesis challenges, with AuSbTe being a semiconductor and Au$_{1.9}$Sb$_{0.46}$Te$_{2.64}$ metallic.

Contribution

It provides new insights into the synthesis, stability, and electronic properties of gold antimony tellurides, which were previously underexplored.

Findings

AuSbTe is an incongruently melting semiconductor.

Au$_{1.9}$Sb$_{0.46}$Te$_{2.64}$ is a congruently melting metal.

Successful synthesis methods for both compounds are identified.

Abstract

Previous studies on natural samples of pampaloite (AuSbTe) revealed the crystal structure of a potentially cleavable and/or exfoliable material, while studies on natural and synthetic montbrayite (Sb-containing Au$_2$Te$_3$) claimed various chemical compositions for this low symmetry compound. Few investigations of synthetic samples have been reported for both materials, leaving much of their chemical, thermal and electronic characteristics unknown. Here, we investigate the stability, electronic properties and synthesis of the gold antimony tellurides AuSbTe and Au$_{1.9}$Sb$_{0.46}$Te$_{2.64}$ (montbrayite). Differential thermal analysis and $\textit{in situ}$ powder x-ray diffraction revealed that AuSbTe is incongruently melting, while Au$_{1.9}$Sb$_{0.46}$Te$_{2.64}$ is congruently melting. Calculations of the band structures and four-point resistivity measurements showed that AuSbTe is a semiconductor and Au$_{1.9}$Sb$_{0.46}$Te$_{2.64}$ a metal. Various synthesis attempts confirmed the limited stable chemical composition of Au$_{1.9}$Sb$_{0.46}$Te$_{2.64}$, identified successful methods to synthesize both compounds, and highlighted the challenges associated with single crystal synthesis of AuSbTe.