Microscopic phase separation in the overdoped region of high-T-c cuprate superconductors

摘要

We propose a phenomenological model for high-T-c superconductors (HTSC) assuming: (1) a microscopic phase separation between superconducting and normal-metal areas in the overdoped region; and (2) existence of a homogeneous superconducting phase only below the pseudo-gap T* line, which shows a sharp reduction towards T* similar to 0 at a mildly overdoped critical concentration x(c). This model explains anomalous doping and temperature dependences of n(s)/m* (superconducting carrier density/effective mass) observed in several overdoped HTSC systems. We point out all analogy to superfluid He-4/He-3 films, and discuss an energetic origin of microscopic phase separation. (C) 2001 Elsevier Science Ltd. All rights reserved. References: 35