Materials Data on Ge3(SbTe3)2 by Materials Project

Abstract

Ge3Sb2Te6 is MAX Phase-like structured and crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three Ge3Sb2Te6 sheets oriented in the (0, 0, 1) direction. there are three inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with nine GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 6–14°. There are three shorter (2.84 Å) and three longer (3.29 Å) Ge–Te bond lengths. In the second Ge4+ site, Ge4+ is bonded to six Te2- atoms to form a mixture of distorted edge and corner-sharing GeTe6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are three shorter (2.84 Å) and three longer (3.40 Å) Ge–Te bond lengths. In the third Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent SbTe6 octahedra, edges with three equivalent SbTe6 octahedra, and edges with six equivalent GeTe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are three shorter (2.84 Å) and three longer (3.29 Å) Ge–Te bond lengths. There are two inequivalent Sb sites. In the first Sb site, Sb is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with nine SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are three shorter (3.01 Å) and three longer (3.21 Å) Sb–Te bond lengths. In the second Sb site, Sb is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent SbTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with nine SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are three shorter (3.02 Å) and three longer (3.18 Å) Sb–Te bond lengths. There are six inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six Sb atoms to form a mixture of edge and corner-sharing TeSb6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. In the second Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb atoms to form TeGe3Sb3 octahedra that share corners with three equivalent TeSb6 octahedra and edges with nine TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 5°. In the third Te2- site, Te2- is bonded to six Ge4+ atoms to form distorted TeGe6 octahedra that share corners with three equivalent TeGe3Sb3 octahedra and edges with nine TeGe6 octahedra. The corner-sharing octahedral tilt angles are 12°. In the fourth Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms. In the fifth Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb atoms to form a mixture of edge and corner-sharing TeGe3Sb3 octahedra. The corner-sharing octahedra tilt angles range from 4–12°. In the sixth Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms.