A Model For The Isotope Effect In High-T-C Superconductors

In this work the isotope coefficient is calculated from the BCS gap equation, using a model with anomalous occupation in the momentum space. The specific case of cuprate oxide superconductors is considered in detail. The isotope exponent alpha(1) is obtained as a function of the anomalous occupation parameter alpha2 and the coupling constant gimel. In particular, the isotope coefficients for YBa2Cu3O7 and Bi2Sr2CaCu2O8 are compared successfully with the experimental results. (C) 2004 Elsevier B.V. All rights reserved.