Band structure and thermoelectric properties of NaxCoO2

The electronic structure and thermoelectric properties of Na x CoO 2 ware calculated by using a full-potential linearized augmented plane-wave (FLAPW) method with a generalized gradient approximation (GGA). The partial occupancy of Na ion was taken account by the virtual-crystal like approximation. The calculated density of states is good agreement with the XPS data. The thermoelectric power was calculated by using the results of the band structure calculation within the linearized Boltzmann equation. Energy dependence of a relaxation time was neglected. The calculated thermoelectric power of Na 0.85 CoO 2 reproduced experimental results very well for the wide temperature range without any adjustable parameter