14-67 J.-B. Bru, A. Delgado de Pasquale and W. de Siqueira Pedra
d Wave Pairing Driven by Bipolaric Modes Related to Giant Electron Phonon Anomalies in High Tc Superconductors (487K, pdf) Sep 15, 14
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Abstract. Taking into account microscopic properties of most usual high Tc superconductors, like cuprates, we define a class of microscopic model Hamiltonians for two fermions (electrons or holes) and one boson (bipolaron) on the two dimensional square lattice. We establish that these model Hamiltonians can show d wave paring at the bottom of their spectrum, despite their space isotropy. This phenomenon appear when a giant electron phonon anomaly is present at the boundaries of the Brillouin zone ( half breathing bond stretching mode), like in doped cuprates. Our results can be used to derive effective electron electron interactions mediated by bipolarons and we discuss regimes where the corresponding model is relevant for the physics of high temperature superconductivity and can be mathematically rigorously studied.

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