ChemInform Abstract: Metallic Ternary Telluride with Sphalerite Superstructure.

Abstract

Metallic Ternary Telluride with Sphalerite Superstructure. -Cu 5Sn2Te7 is prepared by melting and annealing stoichiometric amounts of the elements (evacuated quartz tubes, 1. 650 C, 7 d, 2. 850 C, 5 d). The compound crystallizes in the monoclinic space group C2 (Z = 2, single crystal XRD) and exhibits a superstructure of sphalerite with tetrahedral coordination of Cu, Sn, and Te atoms in an adamantane-like arrangement. The material exhibits metallic behavior with p-type charge carriers and an electrical conductivity of 9.8 x 10 5 S/m at 300 K. Hall effect measurements further confirm holes as charge carriers with a carrier density of 1.39 x 10 21 cm -3 and Hall mobility of 4.5 cm 2 /(V s) at 300 K. Electronic band structure calculations indicate the presence of a finite density of states around the Fermi level and agree well with the p-type metallic conductivity. The high thermal conductivity of 15.1 W/(m K) at 300 K coupled with the low Seebeck coefficient results in a poor thermoelectric figure of merit. -(ADHIKARY, A.; MOHAPATRA, S.; LEE, S. H.; HOR, Y. S.; ADHIKARI, P.; CHING, W.-Y.; CHOUDHURY*, A.; Inorg. Chem. 55 (2016) 5, 2114-2122, http://dx.doi.org/10.1021/acs.inorgchem.5b02516 ; Dep. Chem., Mo. Univ. Sci. Technol., Rolla, MO 65409, USA; Eng.) -J. Schramke 20-005