%0 Journal Article
%T Anomalous impurity effects in nonadiabatic superconductors
%A M. Scattoni
%A C. Grimaldi
%A L. Pietronero
%J Physics
%D 1998
%I arXiv
%R 10.1209/epl/i1999-00429-5
%X We show that, in contrast with the usual electron-phonon Migdal-Eliashberg theory, the critical temperature Tc of an isotropic s-wave nonadiabatic superconductor is strongly reduced by the presence of diluted non-magnetic impurities. Our results suggest that the recently observed Tc-suppression driven by disorder in K3C60 [Phys. Rev. B vol.55, 3866 (1997)] and in Nd(2-x)CexCuO(4-delta) [Phys. Rev. B vol.58, 8800 (1998)] could be explained in terms of a nonadiabatic electron-phonon coupling. Moreover, we predict that the isotope effect on Tc has an impurity dependence qualitatively different from the one expected for anisotropic superconductors.
%U http://arxiv.org/abs/cond-mat/9812192v2