Structural investigation of Ge3Sb2Te6, an intermetallic compound in the GeTe–Sb2Te3 homologous series

Abstract

Ge 3 Sb 2 Te 6 was analyzed in detail using an x-ray diffraction method. The crystal of this material in the space group R3¯m is characterized as a 33-layered cubic close-packed stacking structure. Te atoms fully occupy their specific layers, whereas Ge and Sb atoms are located in other layers thus causing partial atomic disordering. Te and Ge∕Sb layers are laminated alternately 11 times to form a NaCl block. Electron density distributions in the crystal were obtained using the maximum entropy method and band calculation, which showed very good agreement with each other. Ge3Sb2Te6 is a compound semiconductor with a very narrow band gap.