Theoretical investigation of the electronic structure and transport properties of Na1+xCo2O4

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DOIResolve DOI: http://doi.org/10.1088/0953-8984/16/36/015
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TypeArticle
Journal titleJournal Of Physics. Condensed Matter
ISSN09538984
Volume16
Issue36
Pages64936505; # of pages: 13
AbstractThe validity of a simple band description for explaining the unexpectedly large thermopower in Na1+xCo2O4 was investigated. Non-spin-polarized and spin-polarized electronic structures of layered cobalt oxides Na1+xCo2O4 are studied by means of first-principles density functional theory calculations. The fractional occupancy of Na is described via two approaches--the virtual crystal approximation and the rigid band model. We also found that the band structure of the valence band is very sensitive to the geometry of the CoO6 'octahedron', and cannot be described by a simple crystal field model. The Seebeck coefficients are calculated from the standard kinetic theory. The calculated thermopower demonstrates the importance of a high density of states close to the Fermi level. The calculated Seebeck coefficient based on the paramagnetic band structure is apparently in good agreement with experimental observation although it has been suggested that spin entropy may dominate the thermopower. However, the calculation failed to account for the observed negative in-plane Hall coefficient.
Publication date
AffiliationNational Research Council Canada; NRC Steacie Institute for Molecular Sciences
Peer reviewedNo
Identifier10451456
NPARC number12338831
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Record identifier708d4819-c269-4490-b476-069883674da6
Record created2009-09-11
Record modified2016-05-09
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