Temperature-Dependence of the Superconducting Condensate and Gap in Bi2sr2ca1cu2o8+X

Using high energy resolution angle-resolved photoemission, we have measured both the superconducting gap and the photoemission superconducting condensate spectral area of Bi2Sr2Ca1Cu1O8+x as a function of temperature in two different locations of the Brillouin zone. We found that the size of superconducting gap along the Gamma - X direction decreases to values indistinguishable from zero for which the gap retains virtually full value along the Gamma - (M) over bar direction. The increased gap anisotropy with increasing temperature is in contrast to what happens for conventional anisotropic superconductors such as lead.