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Temperature Dependence of the Chemical Potential in NaxCoO2: Implications for the Large Thermoelectric Power

Y. Ishida·H. Ohta·A. Fujimori·H. Hosono
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Abstract

We have performed a temperature-dependent photoemission study of a NaxCoO2 (x~0.8) epitaxial thin film prepared by the reactive solid-phase epitaxy method. The chemical potential shift as a function of temperature was derived from the Co 3d peak shift, and revealed a crossover from the degenerate Fermion state at low temperatures to the correlated hopping state of Co3+/Co4+ mixed-valence at high temperatures. This suggests that the large thermoelectric power at high temperatures should be considered in the correlated hopping picture.

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Y. Ishida, H. Ohta, A. Fujimori, H. Hosono. 2006-07-15. Temperature Dependence of the Chemical Potential in NaxCoO2: Implications for the Large Thermoelectric Power. https://doi.org/10.1143/jpsj.76.103709

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