Berlin 2012 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 17: Superconductivity: Fe-based Superconductors - 122 Part 2 & Theory
TT 17.8: Talk
Tuesday, March 27, 2012, 11:30–11:45, H 2053
(contribution withdrawn)Small-q Phonon Mediated Unconventional Superconductivity in the Iron Pnictides — •Alex Aperis1, Panagiotis Kotetes1,2, Georgios Varelogiannis1, and Peter M. Oppeneer3 — 1Department of Physics, National Technical University of Athens, GR-15780 Athens, Greece — 2Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany — 3Department of Physics and Materials Science, Uppsala University, Box 530, S-751 21 Uppsala, Sweden
We report full momentum-dependent self-consistent calculations of the gap symmetry for the iron-based high-temperature superconductors using a realistic small-q phonon mediated pairing potential within a four-band model. When both electron and hole Fermi surface pockets are present, we obtain the nodeless s± state that was first encountered in a spin-fluctuations mechanism picture. Nodal gap structures such as dx2−y2, s±+dx2−y2 and even a p-wave triplet state, are accessible upon doping within our phononic mechanism [1]. Our results resolve the conflict between phase sensitive experiments reporting a gap changing sign attributed previously only to a non-phononic mechanism and isotope effect measurements proving the involvement of phonons in the pairing. Application of our theory to specific members of the pnictide family will also be briefly discussed.
A. Aperis et al., Phys. Rev. B 83, 092505 (2011).