Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 30: Superconductivity - Poster Session
TT 30.24: Poster
Monday, March 31, 2014, 15:00–19:00, P2
Effect of weak disorder on the phase competition in iron pnictides — •Mareike Hoyer1, Sergey Syzranov1,2, and Jörg Schmalian1,3 — 1Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, Karlsruhe, Germany — 2Department of Physics, University of Colorado, Boulder, Colorado, USA — 3Institut für Festkörperphysik, Karlsruher Institut für Technologie, Karlsruhe, Germany
We investigate the phase competition between magnetism and superconductivity for iron pnictides in the presence of weak disorder. The competition of these two ordered states has been studied in detail by Fernandes and Schmalian [1] who came to the conclusion that in the case of unconventional s+− pairing, the superconducting and antiferromagnetic phase may coexist microscopically but are near to a parameter regime of mutual exclusion. Correspondingly, the multicritical point in the phase diagram is close to the transition from a tetracritical to a bicritical point.
Close to the multicritical point, the free energy of the system can be expanded simultaneously in terms of magnetic and superconducting order parameters and the coefficients can be determined microscopically. We include the effect of impurity scattering in the model and investigate its influence on the phase diagram of iron pnictides.
Rafael M. Fernandes and Jörg Schmalian, Phys. Rev. B 82, 014521