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TT: Fachverband Tiefe Temperaturen
TT 32: Superconductivity: Theory 2
TT 32.1: Vortrag
Mittwoch, 18. März 2020, 09:30–09:45, HSZ 103
Josephson lattice model for phase fluctuations of local pairs in copper oxide superconductors — •Sergey Brener1,2, Malte Harland1, Alexander Lichtenstein1, and Mikhail Katsnelson3 — 1Universität Hamburg — 2The Hamburg Centre for Ultrafast Imaging — 3Radboud Universiteit, Nijmegen, Niederlande
We derive an expression for the effective Josephson coupling from the microscopic Hubbard model. It serves as a starting point for the description of phase fluctuations of local Cooper pairs in dx2−y2-wave superconductors in the framework of an effective XY model of plaquettes, the Josephson lattice. The expression for the effective interaction is derived by means of the local-force theorem, and it depends on local symmetry-broken correlation functions that we obtain using the cluster dynamical mean-field theory. Moreover, we apply the continuum limit to the Josephson lattice to obtain an expression for the gradient term in the Ginzburg-Landau theory and compare predicted London penetration depths and Kosterlitz-Thouless transition temperatures with experimental data for YBa2Cu3O7−x.