Regensburg 2010 – wissenschaftliches Programm
TT 24.10: Vortrag
Mittwoch, 24. März 2010, 16:45–17:00, H19
Microscopic approach to high-temperature superconductors: Superconducting phase — •Steffen Sykora1,2 and Klaus W. Becker1 — 1Institut für Theoretische Physik, Technische Universität Dresden, Germany — 2Department of Physics and Astronomy, Rutgers University, USA
An understanding of the superconducting pairing mechanism of the high-temperature superconductors leading to an unprecedented high transition temperature Tc is still lacking. Starting from the t-J model, in this talk we present a microscopic approach to investigate physical properties of the superconducting phase in the framework of a novel renormalization scheme called PRM. This approach is based on a stepwise elimination of high-energy transitions using unitary transformations. We find a renormalized ’free’ Hamiltonian for correlated electrons for the superconducting phase. Our microscopic approach allows us to explain the experimental findings in the underdoped as well as in the optimal hole doping regime. Our results turn out to be in good agreement with experiment: The superconducting order parameter shows d-wave symmetry with a coherence length of a few lattice constants. In good agreement with experiments, we find no superconducting solutions for very small hole doping. Furthermore, we calculate the ARPES spectral function along the Fermi surface. The spectra display peak-like structures which are caused alone by coherent excitations in a small range around the Fermi energy.