The Hunds Superconductor Li(Fe,Co)As


Abstract in English

We combine transport, angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy to investigate several low energy manifestations of the Hund coupling in a canonical FeSC family Li(Fe,Co)As. We determine the doping dependence of the coherent-incoherent crossover temperature and the quasi-particle effective mass enhancement in the normal state. Our tunneling spectroscopy result in the superconducting state supports the idea that superconductivity emerging from Hunds metal state displays a universal maximal superconducting gap vs transition temperature (2$Delta_{max}/k_{B}T_{c}$) value, which is independent of doping level and $T_{c}$.

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