Unconventional Superconductivity with a Sign Reversal in the Order Parameter of LaFeAsO 1-x F x
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It is argued that the newly discovered superconductivity in a nearly magnetic, Fe-based layered compound is unconventional and mediated by antiferromagnetic spin fluctuations, though different from the usual superexchange and specific to this compound.Abstract:
We argue that the newly discovered superconductivity in a nearly magnetic, Fe-based layered compound is unconventional and mediated by antiferromagnetic spin fluctuations, though different from the usual superexchange and specific to this compound. This resulting state is an example of extended s-wave pairing with a sign reversal of the order parameter between different Fermi surface sheets. The main role of doping in this scenario is to lower the density of states and suppress the pair-breaking ferromagnetic fluctuations.read more
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Point-contact Andreev-reflection spectroscopy in ReFeAsO1−xFx (Re = La, Sm): Possible evidence for two nodeless gaps
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