ANISOTROPIC ELECTRON COUPLING AS A PHENOMENOLOGICAL MODEL FOR HIGH-TCSUPERCONDUCTORS

A three-dimensional weak coupling BCS model with an anisotropic pairin g interaction m momentum space is reported. It exhibits an anisotropic gap in accord with recent experimental observations for high-T(c) oxi des. The gap ratio 2DELTA/k(B)T(c) is calculated as a function of the anisotropy ratio of the electron pairing. It is found that the mean ga p ratio decreases with increasing anisotropy of the electron pairing, whereas the maximum gap ratio increases. Assuming a unique strength of the effective electron interaction the transition temperature turns o ut to be always larger than in the isotropic case. The temperature dep endence of the gap in the Cu-O plane and along the c axis of Y-Ba-Cu-O is presented.