Is the Superconductiong State for the Cuprates Reached through a Percolation Transition?

Several recent experiments have revealed that the charge density ρ in a given compound (mostly underdoped) is intrinsic inhomogeneous with large spatial variations. Therefore it is appropriate to define a local charge density ρ(r). These differences in the local charge concentration yield insulator and metallic regions, either in an intrinsic granular or in a stripe morphology. In the metallic region, the inhomogeneous charge density produces spatial or local distributions of superconducting critical temperatures Tc(r) and zero temperature gap ∆0(r). We propose that the superconducting phase in high-Tc oxides is reached when the temperature reachs a value which superconduction regions with different critical temperatures percolates. We show also that this novel approach is able to reproduce the phase diagram for a family of cuprates and provides new insights on several experimental features of high-Tc oxides.