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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Bi2Te4Pb by Materials Project

PbBi2Te4 is MAX Phase-like structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three PbBi2Te4 sheets oriented in the (0, 0, 1) direction. Pb2+ is bonded to six equivalent Te2- atoms to form PbTe6 octahedra that share corners with six equivalent BiTe6 octahedra, edges with six equivalent PbTe6 octahedra, and edges with six equivalent BiTe6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Pb–Te bond lengths are 3.28 Å. Bi3+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three equivalent PbTe6 octahedra, edges with three equivalent PbTe6 octahedra, and edges with six equivalent BiTe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (3.10 Å) and three longer (3.31 Å) Bi–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Bi3+ atoms. In the second Te2- site, Te2- is bonded to three equivalent Pb2+ and three equivalent Bi3+ atoms to form a mixture of edge and corner-sharing TeBi3Pb3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2Te4Pb by Materials Project

PbBi2Te4 is Caswellsilverite-like structured and crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three PbBi2Te4 sheets oriented in the (0, 0, 1) direction. Pb2+ is bonded to six Te2- atoms to form PbTe6 octahedra that share corners with three equivalent BiTe6 octahedra, edges with three equivalent BiTe6 octahedra, and edges with six equivalent PbTe6 octahedra. The corner-sharing octahedral tilt angles are 9°. There are three shorter (3.08 Å) and three longer (3.52 Å) Pb–Te bond lengths. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six Te2- atoms to form a mixture of corner and edge-sharing BiTe6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are three shorter (3.09 Å) and three longer (3.36 Å) Bi–Te bond lengths. In the second Bi3+ site, Bi3+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three equivalent PbTe6 octahedra, corners with three equivalent BiTe6 octahedra, edges with three equivalent PbTe6 octahedra, and edges with nine BiTe6 octahedra. The corner-sharing octahedra tilt angles range from 3–9°. There are three shorter (3.12 Å) and three longer (3.23 Å) Bi–Te bond lengths. There are four inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Pb2+ atoms. In the second Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Bi3+ atoms. In the third Te2- site, Te2- is bonded to six Bi3+ atoms to form TeBi6 octahedra that share corners with three equivalent TeBi3Pb3 octahedra and edges with nine TeBi6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the fourth Te2- site, Te2- is bonded to three equivalent Pb2+ and three equivalent Bi3+ atoms to form a mixture of corner and edge-sharing TeBi3Pb3 octahedra. The corner-sharing octahedral tilt angles are 3°.

36 MATERIALS SCIENCE↗