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Coupled Modes

Coupled multi-mode theory for iron-based superconductors


The rapidly extending realm of high-temperature superconductors has been enriched recently by a new class of materials, the iron based superconductors (FeSC). Like many other high-temperature superconducting materials, these compounds crystallize in strongly anisotropic lattices: one can identify quasi-two-dimensional subsystems which contain the electrons that are subject to superconducting pairing. A specific feature of the electronic structure of FeSC is the multipocket Fermi surface, mostly semi-metallic (with both hole and electron pockets), although some superconducting materials possess either only electron or only hole pockets. Most of the FeSC materials demonstrate an interplay between different electronic instabilities of the pristine normal metal phases: spin-density wave (SDW) type itinerant antiferromagnetism, high- temperature superconductivity and orbital ordering.

In recent publication in Scientific Reports a collaboration between ICTP, Institute for Theoretical Solid State Physics, IFW Dresden (Germany) and School of Physics and Astronomy, Tel Aviv University (Israel) has been proposed a theory describing the coupling of fluctuating modes in a regime when the instabilities emerge. In particular, it was shown that the mutual influence of superconducting and magnetic fluctuations results in suppression of the magnetic transition keeping the superconducting transition intact.

The results published in Scientific Reports shed a light on the interplay between different competing fluctuating modes in strongly correlated materials and provide possible explanation for some exotic behavior of iron-based superconductors.

For more details see the publication: Kiselev, M. N. et al. Coupled multiple-mode theory for s± pairing mechanism in iron based superconductors. Sci. Rep. 6, 37508; doi: 10.1038/srep37508 (2016)