Disorder-induced gap in the normal density of states of the organic superconductor κ-(BEDT-TTF)₂Cu[N(CN)₂]Br

2014/10/20 by Diehl, Sandra, Methfessel, Torsten, Müller, Jens +4
#FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)

paper · doi:10.48550/arxiv.1410.5245

Abstract

The density of states of the organic superconductor κ-(BEDT-TTF)₂Cu[N(CN)₂]Br, measured by scanning tunneling spectroscopy on in-situ cleaved surfaces, reveals a logarithmic suppression near the Fermi edge persisting above the critical temperature T_c. A soft Hubbard gap as predicted by the Anderson-Hubbard model for systems with disorder exactly describes the experimentally observed suppression. The electronic disorder also explains the diminished coherence peaks of the quasiparticle density of states below T_c.

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