Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 2: SC: Properties, Electronic Structure, Mechanisms 1
TT 2.4: Vortrag
Montag, 14. März 2011, 11:15–11:30, HSZ 301
Low-energy kink in the nodal dispersion of copper-oxide superconductors: Insights from Dynamical Mean Field Theory — •Johannes Bauer1 and Giorgio Sangiovanni2 — 1Max-Planck Institute for Solid State Research, Heisenbergstr.1, 70569 Stuttgart — 2Institute of Solid State Physics, Vienna University of Technology, 1040 Vienna, Austria
Motivated by the observation in copper-oxide high-temperature superconductors,
we investigate the appearance of kinks in the electronic dispersion due to
coupling to phonons for a system with strong electronic repulsion.
We study a Hubbard model supplemented by an electron-phonon coupling of
Holstein type within Dynamical Mean Field Theory (DMFT) utilizing Numerical
Renormalization Group as impurity solver. Paramagnetic DMFT solutions in the
presence of large repulsion show a kink only for large values of the
electron-phonon coupling λ or large doping and, contrary to the
conventional electron-phonon theory, the position of such a kink can be shifted to
energies larger than the renormalized phonon frequency ω0r.
When including antiferromagnetic correlations we find a
stronger effect of the electron-phonon interaction on the electronic
dispersion due to a cooperative effect and a visible kink at ω0r,
even for smaller λ [1]. Our results provide a scenario of a kink position
increasing with doping, which can be related to recent photoemission
experiments on Bi-based cuprates.
J. Bauer and G. Sangiovanni, Phys. Rev. B. 82, 184535 (2010).