The gap function in YBa2Cu3O7

We hate solved the four-dimensional anisotropic Eliashberg gap equation for YBa2Cu3O7 (YBCO) using the calculated electronic structure and the electro n-phonon interaction matrix elements. The calculated T-c for YBCO is about 89 K for mu* = 0.1. At or slightly above the transition temperature T-c, th e real part of the gap function Delta(k, 0), for all the k-points on the Fe rmi surface, becomes zero and the material is not superconducting. However, the energy gap function Delta(k, omega) is still nonzero for omega > 0 for some electronic states, leading to a pseudo-gap behavior in YBCO.