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TT: Fachverband Tiefe Temperaturen

TT 17: SC: Iron-Based Superconductors - Theoretical Approaches

TT 17.7: Vortrag

Dienstag, 23. März 2010, 16:00–16:15, H20

Superconductivity in the Fe-Pnictides - From first principle calculations to effective RG studies — •Christian Platt¹, Ronny Thomale², Andrei Bernevig², Carsten Honerkamp³, and Werner Hanke¹ — ¹Universität Würzburg — ²Princeton University — ³RWTH Aachen

The functional Renormalization Group (fRG) is used to determine the superconducting (SC) mechansim in the ferropnictides, with the main emphasis on distiguishing universal and material-specific aspects. To this end we use a five-band d-orbital whose interactions, in contrast to earlier fRG studies, are not taken as scalar model parameters, but calculated "a priori" from constrained RPA calculations. We universally find a SC pairing instability, driven by inter-Fermi surface (FS) scattering and resulting in a sign-changing s+- wave order parameter. However, the gap anisotropy is shown to be dependent on material-specific orbital parameter deviations not only by the "non-interacting" (i.e. LDA) part of the d-orbital Hamiltonian, but also by self-energy corrections.