Crystal growth and characterization of the narrow-band-gap semiconductors OsPn2 (Pn = P, As, Sb)

Daniel E. Bugaris, Christos D. Malliakas, Daniel P. Shoemaker, Dat T. Do, Duck Young Chung, Subhendra D. Mahanti, Mercouri G. Kanatzidis

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Abstract

Using metal fluxes, crystals of the binary osmium dipnictides OsPn2 (Pn = P, As, Sb) have been grown for the first time. Single-crystal X-ray diffraction confirms that these compounds crystallize in the marcasite structure type with orthorhombic space group Pnnm. The structure is a threedimensional framework of corner- and edge-sharing OsPn6 octahedra, as well as [Pn24-] anions. Raman spectroscopy shows the presence of P-P single bonds, consistent with the presence of [Pn2-4] anions and formally Os4+ cations. Optical-band-gap and high-temperature electrical resistivity measurements indicate that these materials are narrow-band-gap semiconductors. The experimentally determined Seebeck coefficients reveal that nominally undoped OsP2 and OsSb2 are n-type semiconductors, whereas OsAs2 is p-type. Electronic band structure using density functional theory calculations shows that these compounds are indirect narrow-band-gap semiconductors. The bonding p orbitals associated with the Pn2 dimer are below the Fermi energy, and the corresponding antibonding states are above, consistent with a Pn-Pn single bond. Thermopower calculations using Boltzmann transport theory and constant relaxation time approximation show that these materials are potentially good thermoelectrics, in agreement with experiment.

Original languageEnglish
Pages (from-to)9959-9968
Number of pages10
JournalInorganic Chemistry
Volume53
Issue number18
DOIs
Publication statusPublished - Sep 15 2014

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

Bugaris, D. E., Malliakas, C. D., Shoemaker, D. P., Do, D. T., Chung, D. Y., Mahanti, S. D., & Kanatzidis, M. G. (2014). Crystal growth and characterization of the narrow-band-gap semiconductors OsPn2 (Pn = P, As, Sb). Inorganic Chemistry, 53(18), 9959-9968. https://doi.org/10.1021/ic501733z