Structural transition in AuAgTe4 under pressure

Abstract

Gold is inert and forms very few compounds. One of the most interesting of those is calaverite AuTe2, which has incommensurate structure and which becomes superconducting when doped or under pressure. There exist a "sibling" of AuTe2 the mineral sylvanite AuAgTe4, which properties are almost unknown. In sylvanite Au and Ag ions are ordered in stripes, and Te6 octahedra around metals are distorted in such a way that Ag becomes linearly coordinated, what is typical for Ag^{1+}, whereas Au is square coordinated - it is typical for d^8 configurations, i.e. one can assign to Au the valence 3+. Our theoretical study shows that at pressure P_C ~ 5 GPa there should occur in it a structural transition such that above this critical pressure Te6 octahedra around Au and Ag become regular and practically identical. Simultaneously Te-Te dimers, existing at P = 0 GPa, disappear, and material from a bad metal becomes a usual metal with predominantly Te 5p states at the Fermi energy. We expect that, similar to AuTe2, AuAgTe4 should become superconducting above P_C.

arXiv comment8 pages, 4 figures

References in corpus (5)

• Crystal field splitting in correlated systems with the negative charge-transfer gap
• Superconductivity Induced by Breaking Te2 Dimers of AuTe2
• Pressure-Induced Superconductivity in Mineral Calaverite AuTe2
• Old puzzle of incommensurate crystal structure of calaverite AuTe${}_2$ and predicted stability of novel AuTe compound
• Effect of Pt substitution on the electronic structure of AuTe2

Cited by in corpus (1)

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