Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 110: Superconductivity: Fe-based Superconductors – Theory
TT 110.3: Vortrag
Freitag, 20. März 2015, 10:00–10:15, H 2053
Superconductivity and Magnetism from First Principles — •Andreas Linscheid, Antonio Sanna, Frank Essenberger, and Eberhard K.U. Gross — Max-Planck-Institut für Mikrostrukturphysik
Magnetism has intriguing effects in superconductors. On the one hand static magnetic fields are known to suppress the superconducting state while dynamic spin-fluctuations are the probable candidate to explain the pairing in the Fe-based Superconductors.
Achieving an ab-initio description is important. First, because this allows to compute the critical field and whether a local coexistence of magnetic and superconducting phases exist. Second, the critical temperature of a material is among the predicted properties which allows to search yet unknown superconductors on a computer.
The Density Functional Theory for Superconductors (SCDFT) has been very successful in predicting Tc of phonon mediated superconductors. We include the magnetic density into SCDFT so that the electronic Kohn-Sham system now reproduces the electronic density n(r), the order parameter of superconductivity χ(r,r′) and the magnetic density m(r). We derive the xc-potential and discuss some first results.
Furthermore, we discuss an effective electron interaction mediated by spin-flip processes based on the exact spin-susceptibility. We drive a xc-functional for SCDFT that includes this effective interaction and present some results.