Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 27: Superconductivity: Cuprate Superconductors
TT 27.7: Vortrag
Mittwoch, 28. März 2012, 13:00–13:15, H 2053
Effect of planar elastic strain on cuprate superconductivity — •Jürgen Röhler — Universität zu Köln, 50937 Köln, Germany
Elastic strain has important effects on the properties of hole doped superconducting cuprates, most significantly on Tc. While c-axis compression primarily enhances the number of hole carriers n, the
intrinsic Tcintr is determined by the in-plane lattice
parameter a, or the area of the CuO2 planes A. For optimal doping, dTc/dn = 0, the available high pressure data suggest Tc ∝ A−2, universally within the various cuprate families [1]. This significant relationship requires A(n) to exhibit an extremum around nopt=0.16, ubiquitously observed as “bulging” anomaly [2] riding the monotonous contraction of A from increasing covalency. We propose to express these findings in terms of the magnetoelastic strain exerted on the CuO2 lattice by pseudo-gapped excitations of preformed 3a hole pairs with nn repulsion [2].
J.S. Schilling in: Handbook of high-temperature
superconductivity: theory and experiment, J.R. Schrieffer, J.S. Brooks (eds.), Springer 2007, p. 427.
J. Röhler, Int. J. Mod. Phys B (2005), 19, 255.