Strong electron correlations in the normal state of FeSe0.42Te0.58


Abstract in English

We investigate the normal state of the 11 iron-based superconductor FeSe0.42Te0.58 by angle resolved photoemission. Our data reveal a highly renormalized quasiparticle dispersion characteristic of a strongly correlated metal. We find sheet dependent effective carrier masses between ~ 3 - 16 m_e corresponding to a mass enhancement over band structure values of m*/m_band ~ 6 - 20. This is nearly an order of magnitude higher than the renormalization reported previously for iron-arsenide superconductors of the 1111 and 122 families but fully consistent with the bulk specific heat.

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