TY - JOUR
T1 - Crystal growth and characterization of the narrow-band-gap semiconductors OsPn2 (Pn = P, As, Sb)
AU - Bugaris, Daniel E.
AU - Malliakas, Christos D.
AU - Shoemaker, Daniel P.
AU - Do, Dat T.
AU - Chung, Duck Young
AU - Mahanti, Subhendra D.
AU - Kanatzidis, Mercouri G.
N1 - Publisher Copyright:
© 2014 American Chemical Society.
PY - 2014/9/15
Y1 - 2014/9/15
N2 - 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.
AB - 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.
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U2 - 10.1021/ic501733z
DO - 10.1021/ic501733z
M3 - Article
AN - SCOPUS:84919734274
SN - 0020-1669
VL - 53
SP - 9959
EP - 9968
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 18
ER -