Magnetism and transport properties of layered rare-earth cobaltates Ln{sub 0.3}CoO{sub 2}
- Institute of Physics ASCR, Cukrovarnická 10, 162 00 Prague 6 (Czech Republic)
- Institute of Inorganic Chemistry ASCR, 250 68 Řež near Prague (Czech Republic)
The ab-initio (GGA+U) electronic structure calculations of layered cobaltates Ln{sub 0.3}CoO{sub 2} (Ln = La, Pr, Nd) prepared by ionic exchange from Na{sub 0.90}CoO{sub 2} precursors have been performed. The data are used for numerical modeling of Seebeck coefficient within Boltzmann transport theory using BoltzTraP program [G. K. H. Madsen and D. J. Singh, Comput. Phys. Commun. 175, 67 (2006)], as well as for determination of the crystal field split levels of rare-earth ions using a method based on a transformation of Bloch states into the basis of Wannier functions [P. Novák et al., Phys. Rev. B 87, 205139 (2013)]. An overall agreement with observed magnetism and transport properties is obtained. In particular, the high p-type thermopower is well reproduced in a broad temperature range, but instead of theoretical linear decrease down to the lowest temperatures, the real systems exhibit an anomalous change of Seebeck sign, which might be related to the change of bare metallic carriers into the polaronic ones.
- OSTI ID:
- 22409970
- Journal Information:
- Journal of Applied Physics, Vol. 117, Issue 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
B CODES
COBALT OXIDES
COMPUTERIZED SIMULATION
CRYSTAL FIELD
ELECTRONIC STRUCTURE
LANTHANUM COMPOUNDS
MAGNETISM
NEODYMIUM COMPOUNDS
PRASEODYMIUM COMPOUNDS
PRECURSOR
P-TYPE CONDUCTORS
SODIUM COMPOUNDS
TEMPERATURE DEPENDENCE
TRANSPORT THEORY