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Electronic Correlations in CoO2, the Parent Compound of Triangular Cobaltates

C. de Vaulx·M. -H. Julien·C. Berthier·S. Hebert·V. Pralong·A. Maignan
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Abstract

A 59Co NMR study of CoO2, the x=0 end member of AxCoO2 (A = Na, Li...) cobaltates, reveals a metallic ground state, though with clear signs of strong electron correlations: low-energy spin fluctuations develop at wave vectors q different from 0 and a crossover to a Fermi-liquid regime occurs below a characteristic temperature T*~7 K. Despite some uncertainty over the exact cobalt oxidation state n this material, the results show that electronic correlations are revealed as x is reduced below 0.3. The data are consistent with NaxCoO2 being close to the Mott transition in the x -> 0 limit.

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C. de Vaulx, M. -H. Julien, C. Berthier, S. Hebert, V. Pralong, A. Maignan. 2007-06-15. Electronic Correlations in CoO2, the Parent Compound of Triangular Cobaltates. https://doi.org/10.1103/physrevlett.98.246402

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