Cooperative effect of phonons and electronic correlations for superconductivity in cobaltates

A. FOUSSATS,1 A. GRECO,1 M. BEJAS,1 AND A. MURAMATSU2

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

Año: 2005 vol. 72 p. 205041 - 205044

0163-1829

We propose that unconventional superconductivity in hydrated sodium cobaltate NaxCoO2 results from aninterplay of electronic correlations and electron-phonon interactions. On the basis of the t−V model plusphonons we found evidence for
a unconventional superconductivity,
b realistic values of Tc, and
c thedome shape existing near x0.35. This picture is obtained for V close to the critical Coulomb repulsion Vc,which separates the uniform Fermi liquid from 3
3 charge-density-wave-ordered phase.