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Cooperative effect of phonons and electronic correlations for superconductivity in cobaltates

A. Foussats·A. Greco·M. Bejas·A. Muramatsu
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Abstract

We propose that unconventional superconductivity in hydrated sodium cobaltate $Na_xCoO_2$ results from an interplay of electronic correlations and electron-phonon interactions. On the basis of the $t-V$ model plus phonons we found evidences for a) unconventional superconductivity, b) realistic values of $T_c$ and c) the dome shape existing near $x \sim 0.35$. This picture is obtained for $V$ close to the critical Coulomb repulsion $V_c$ which separates the uniform Fermi liquid from $\sqrt{3} \times \sqrt{3}$ CDW ordered phase.

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A. Foussats, A. Greco, M. Bejas, A. Muramatsu. 2005-07-28. Cooperative effect of phonons and electronic correlations for superconductivity in cobaltates. https://doi.org/10.1103/physrevb.72.020504

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