Deutschen Physikalischen Gesellschaft

A. MURAMATSU; A. FOUSSATS; A. GRECO; M. BEJAS

Berlin

Congreso; Deutschen Physikalischen Gesellschaft; 2005

We propose that unconventional superconductivity in hydrated sodium cobaltate $Na_xCoO_2$ results from an interplayof electronic correlations and electron-phonon interactions.On the basis of the $t-V$ model plus phononswe 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 theuniform Fermi liquid from $sqrt{3} imes sqrt{3}$ CDW ordered phase.