Percolative model of nanoscale phase separation in high-temperature superconductors

Abstract

The nature of the phase diagrams of high-temperature superconductors is clarified by discussing two kinds of phase diagram: that of the host crystalline lattice, and that of the dopant glass. The latter is associated with changes in the electronic properties, while the former is much more accessible to direct experimental identification, by diffraction, of nanoscale phase separation. Careful examination of electronic properties in both the normal and the superconductive states reveals that there are several electronic miscibility gaps in YBa₂Cu₃O_x and La_2-x Sr_xCuO₄ that have been previously overlooked. Recent experiments on the pseudogap in Bi₂Sr_1.6La_0.4CuO_y also reveal an electronic miscibility gap.