| The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) unconventional superconducting state has suddenly gained renewed interest recently because of its possible realization in organic superconductors, optical lattices, and in the heavy fermion superconductor CeCoIn5 (recent studies suggest that the state considered in CeCoIn5 is much more complex than pure FFLO). In CeCoIn5 spin dependence of quasiparticle masses has also been observed recently by means of the de Haas-van Alphen measurements. The spin-dependence of the quasiparticle masses is a hallmark of strong electron correlations. Therefore, the question arises as to what extent these correlations affect the FFLO state. Here we show that the appearance of the spin-split masses essentially extends the regime of temperature and applied magnetic field, in which FFLO state is stable, and thus, it is claimed to be very important for the phase detectability. Furthermore, we analyze the Andreev reflection from the FFLO superconductor and provide conductance spectra for a normal metal - FFLO superconductor junction, which could lead to experimental verification of the presented results. |
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