Materials Data on Ge2Sb2Te5 by Materials Project

Abstract

Ge2Sb2Te5 is MAX Phase-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ge2Sb2Te5 sheet oriented in the (0, 0, 1) direction. 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 (3.30 Å) Ge–Te bond lengths. Sb1+ 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 equivalent SbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are three shorter (3.02 Å) and three longer (3.19 Å) Sb–Te bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six equivalent Sb1+ atoms to form TeSb6 octahedra that share corners with six equivalent TeGe3Sb3 octahedra and edges with twelve TeSb6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the second Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb1+ atoms to form a mixture of edge and corner-sharing TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 4°. In the third Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Ge4+ atoms.