Synthesis of layered gold tellurides AuSbTe and Au_2Te_3 and their semiconducting and metallic behavior

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_2Te_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_1.9Sb_0.46Te_2.64 (montbrayite). Differential thermal analysis and in situ powder x-ray diffraction revealed that AuSbTe is incongruently melting, while Au_1.9Sb_0.46Te_2.64 is congruently melting. Calculations of the band structures and four-point resistivity measurements showed that AuSbTe is a semiconductor and Au_1.9Sb_0.46Te_2.64 a metal. Various synthesis attempts confirmed the limited stable chemical composition of Au_1.9Sb_0.46Te_2.64, identified successful methods to synthesize both compounds, and highlighted the challenges associated with single crystal synthesis of AuSbTe.