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TT: Fachverband Tiefe Temperaturen

TT 98: Poster Session: Superconductivity

TT 98.18: Poster

Donnerstag, 15. März 2018, 15:00–19:00, Poster B

Plaquette Valence Bond Theory of High-Temperature Superconductivity — •Malte Harland¹, Mikhail I. Katsnelson², and Alexander I. Lichtenstein¹ — ¹Universität Hamburg, Hamburg, Germany — ²Radboud University Nijmegen, Nijmegen, The Netherlands

We present a strong-coupling theory of high-temperature superconductivity in the cuprates based on a quantum critical point of the two-by-two Hubbard Plaquette. This point is characterized by the crossing of the particle number sectors N=2,3,4. The groundstates close to the quantum critical point are spin-doublets and spin-singlets supporting the idea of resonating valence bonds on the Plaquette. Embedding the Plaquette in an environment of other Plaquettes we find a d_x²−y²-wave superconducting order parameter where the electrons are on the border between itinerant and localized behavior and investigate its competition with other orders. The bottom-up approach enables us to investigate the superconductivity’s dependence on microscopic parameters such as, e.g. the next-nearest-neighbour hopping. We provide finite-temperature results obtained by the Dynamical Mean-Field theory, that gives an exact solution of our model.