Tetradymite-type tellurides and related compounds: Real-structure effects and thermoelectric properties

Abstract

Many crystal structures of layered tellurides contain building blocks derived from the structure of tetradymite. Stable phases often form homologous series of discrete compounds. Metastable phases and high-temperature phases are highly disordered but the short-range order often corresponds to the structure of stable phases. The complex interplay of phase transitions, diffusion phenomena, metric distortion and nanostructuring in ternary and multinary tellurides requires a broad spectrum of analytical methods. However, this interplay leads to materials with very interesting thermoelectric properties when stable phases are gradually approached from metastable ones by partial ordering, especially by two-dimensional defect ordering. Real-structure effects strongly influence these properties and their tuning can be used to optimize the materials. Known phase-change materials for data storage as well as minerals may point to chemical systems where efficient thermoelectrics can be found.