2002/12/31 by Y. J. Uemura
Engineering · Physics and Astronomy · #Coherence length #Condensed matter physics #Cuprate #Josephson effect #Phase (matter) #Phase diagram #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Superconducting Materials and Applications #Superconductivity #Superconductivity in MgB2 and Alloys #Supercurrent #Superfluidity #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1016/s0038-1098(02)00665-8
21 pages, 18 figures, invited papter presented at the HTSC Workshop, Williamsburg, Virginia, June 7-8, 2002, to appear in Solid State Communications (Special Issue edited by A.J. Millis, S. Uchida, Y.J. Uemura): contact [email protected]
arxiv created 2002/12/31 · openalex publication_date 2003/03/25 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Extensive muon spin relaxation measurements have been performed to determine the magnetic field penetration depth in high-Tc cuprate superconductors with simple hole doping, Zn-doping, overdoping, and formation of static SDW nano islands. System dependence of ns/m* (superconducting carrier density / effective mass) reveals universal correlations between Tc and ns/m* in all these cases with / without perturbation. Evidence for spontaneous and microscopic phase separation was obtained in the cases with strong perturbation, i.e., Zn-doping. overdoping and SDW nano-islands. The length scale of this heterogeneity is shown to be comparable to the in-plance coherence length. We discuss implications of these results on condensation mechanisms of HTSC systems, resorting to an analogy with He films, on regular and porous media, reminding essential features of Bose-Einstein, BCS and Kosterlitz-Thouless condensation/transition in 2-d and 3-d systems, and comparing models of BE-BCS crossover and phase fluctuations. We propose a new phase diagram for HTSC systems based on distinction between pair formation and superconducting phase fluctuations in the pseudogap region and spontaneous phase separation in the overdoped region. We also remind anomaly in BEDT and A3C60 systems similar to that in overdoped cuprates, seen in the evolution from superconducting to metallic ground state.