Describing How the Superconducting Transition in La_2CuO_(4+y) Is Related to the i-O Phase Separation

摘要

The phase separation of oxygen interstitial in the spacer layers separating the CuO_2 planes in the high critical temperature superconductor La_2CuO_(4+y) was studied by Poccia et al. (Nat. Mater. 10:733, 2011). We model this transition by the electronic charge in the planes that can be described by the Cahn-Hilliard theory, with the formation of clusters of low and high densities separated by potential barriers. The charge diffusion into bound regions minimizes the energy and favors the formation of Cooper pairs. Self-consistent calculations yield local dependent superconducting amplitudes Δ_(sc)(r), and the resistivity transition at T_c is driven by Josephson coupling among these nanoscale clusters.