Eur. Phys. J. B 9, 201-206 (1999)
https://doi.org/10.1007/s100510050757

Normal and superconducting state in the presence of forward electron-phonon and impurity scattering

¹ P.N. Lebedev Physical Institute, Moscow, Russia
² Institut für Theoretische Physik, Universität Tübingen, Germany
³ Physikalisches Institut, Universität Bayreuth, 95440 Bayreuth, Germany
⁴ Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
⁵ Joint Institute for Nuclear Research, 141980 Dubna, Russia

Received: 1 July 1998
Published online: 15 May 1999

Abstract

By assuming that the superconducting pairing is due to the forward E-P scattering (FEP pairing) it is shown that the critical temperature of clean systems T_c0 depends linearly on the E-P coupling constant λ and the isotope effect is very small. Impurities with the pronounced forward scattering (FS impurities) change analytical properties of the quasiparticle Green's function substantially compared to the case of the isotropic scattering. The FS impurities are pair-breaking and affect in the same way s- and d-wave FEP pairing making in the dirty limit.The usual isotropic impurity scattering is pair-weakening for s-wave and pair-breaking for the d-wave FEP pairing.