Materials Data on GeSb4Te7 by Materials Project
Ge1Sb4Te7 is MAX Phase-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ge(SbTe2)2 sheet oriented in the (0, 0, 1) direction and one Sb2Te3 sheet oriented in the (0, 0, 1) direction. In the Ge(SbTe2)2 sheet, Ge4+ is bonded to six equivalent Te2- atoms to form GeTe6 octahedra that share corners with six equivalent SbTe6 octahedra, edges with six equivalent GeTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 5°. All Ge–Te bond lengths are 3.02 Å. Sb+2.50+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with three equivalent GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six equivalent SbTe6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (3.02 Å) and three longer (3.21 Å) Sb–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Sb+2.50+ atoms to form a mixture of corner and edge-sharing TeGe3Sb3 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Sb+2.50+ atoms. In the Sb2Te3 sheet, Sb+2.50+ is bonded to six Te2- atoms to form a mixture of corner and edge-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (3.03 Å) and three longer (3.19 Å) Sb–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six equivalent Sb+2.50+ atoms to form edge-sharing TeSb6 octahedra. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Sb+2.50+ atoms.