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Title: Electrical/thermal transport and electronic structure of the binary cobalt pnictides CoPn{sub 2} (Pn = As and Sb)

We demonstrate the electrical and thermal transport properties of polycrystalline CoPn{sub 2} (Pn = As and Sb) between 300 and 900 K. CoAs{sub 2} shows semiconducting electrical transport up to 900 K, while CoSb{sub 2} exhibits degenerate conduction. Sign inversion of the Seebeck coefficient is observed at ∼310 and ∼400 K for CoAs{sub 2} and CoSb{sub 2}, respectively. Thermal conductivity at 300 K is 11.7 Wm{sup −1}K{sup −1} for CoAs{sub 2} and 9.4 Wm{sup −1}K{sup −1} for CoSb{sub 2}. The thermoelectric power factor of CoAs{sub 2} is ∼10 μWcm{sup −1}K{sup −2}, although the dimensionless figure of merit is limited to ∼0.1 due to relatively high thermal conductivity. Using electronic structure calculations, the band gap value is calculated to be 0.55 eV for CoAs{sub 2} and 0.26 eV for CoSb{sub 2}.
Authors:
; ; ;  [1]
  1. Department of Applied Physics and Physico-Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522 (Japan)
Publication Date:
OSTI Identifier:
22493910
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 6; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; ANTIMONIDES; COBALT; COBALT ARSENIDES; ELECTRIC CONDUCTIVITY; ELECTRONIC STRUCTURE; ENERGY GAP; EV RANGE; PERFORMANCE; POLYCRYSTALS; SEEBECK EFFECT; SEMICONDUCTOR MATERIALS; TEMPERATURE DEPENDENCE; THERMAL CONDUCTIVITY; THERMOELECTRIC PROPERTIES