Universal Journal of Physics and Application Vol. 12(4), pp. 76 - 81
DOI: 10.13189/ujpa.2018.120403
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Plaquette Valence Bond Theory of Cuprate High-Temperature Superconductivity


Malte Harland 1,*, Tim Berberich 1, Mikhail I. Katsnelson 2, Alexander I. Lichtenstein 1,3
1 Institute of Theoretical Physics, University of Hamburg, Hamburg, 20355, Germany
2 Institute for Molecules and Materials, Radboud University, Nijmegen, 6525AJ, the Netherlands
3 The Hamburg Centre for Ultrafast Imaging, Hamburg, 22761, Germany

ABSTRACT

We investigate the phenomenon of high-temperature superconductivity within a strong coupling perspective. The occurence is traced to a quantum critical point that is in the phase diagram of the plaquette's t; t0-Hubbard model. We develop a bottom-up approach combining several methods, i.e. exact diagonalization of an isolated plaquette, the Lanczos-method for a plaquette within a bath and cluster dynamical Mean-Field theory with continuous time quantum Monte-Carlo solver to embedd the plaquette in a lattice environment. The quantum critical point is located where the N = 2; 3; 4-sectors of the plaquette cross. This point is also found to show optimal doping. The wave order turns out to be largest at the localized-itinerant transition of the electrons. Furthermore, we present an explenation for the pseudo-gap phenomenon, that is explained by a soft mode related to local singlets of the plaquette. The theory presented here is similar to the resonating valence bond theory, but stresses the importance of local singlets.

KEYWORDS
Quantum Critical Point, Plaquette, Hubbard Model, Resonating Valence Bonds

Cite this paper
Malte Harland , Tim Berberich , Mikhail I. Katsnelson , Alexander I. Lichtenstein . "Plaquette Valence Bond Theory of Cuprate High-Temperature Superconductivity." Universal Journal of Physics and Application 12.4 (2018) 76 - 81. doi: 10.13189/ujpa.2018.120403.