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O: Fachverband Oberflächenphysik

O 44: Low-Dimensional Systems: 2D - Theory (TT jointly with O)

O 44.12: Vortrag

Mittwoch, 2. April 2014, 12:30–12:45, BEY 81

Unconventional superconductivity in the two dimensional Edwards model — •Dai-Ning Cho and Steffen Sykora — Institute for Theoretical Solid State Physics, IFW Dresden, D-01069 Dresden, Germany

The nature of charge transport within a correlated background medium can be described by spinless fermions coupled to bosons in the model introduced by Edwards. Employing the analytical projector-based renormalization method (PRM), we obtain a solvable effective Hamiltonian H which consists of a decoupled system of renormalized conduction electrons and a bosonic term with renormalized dispersion ω_q which is generated naturally within the renormalization procedure. This method has been applied successfully to the 1D Edwards model where unbiased numerical results could be confirmed by the PRM. For the 2D model we show results for the effective one-particle dispersions of electrons and bosons in the whole Brillouin zone and for different values of the electron filling. In particular, we find strong dispersion of boson modes indicating a quantum phase transition to an unconventional superconducting state mediated by strong charge fluctuations. We show that the pairing changes its character from s- to d-wave symmetry.