title: Evidence for itineracy in the anticipated Kondo insulator FeSi: a quantitative determination of the band renormalization.
abstract: A comparison of high-resolution, angle-resolved photoemission spectroscopy (ARPES) data with ab initio band-structure calculations by density functional theory for the anticipated Kondo insulator FeSi shows that the experimental dispersions can quantitatively be described by an itinerant behavior provided that an appropriate self-energy correction is included, whose real part describes the band renormalization due to interactions of the Fe 3d electrons. The imaginary part of the self-energy, on the other hand, determines the linewidth of the quasiparticle peaks in the ARPES data. We use a model self-energy which consistently describes both the renormalized single-particle dispersion and the energy-dependent linewidth of the Fe 3d bands. These results are clear evidence that FeSi is an itinerant semiconductor whose properties can be explained without a local Kondo-like interaction.
authors.affiliation: Universität Würzburg, Experimentelle Physik II, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Klein
authors.forename: D
authors.initials: D
authors.lastname: Zur
authors.forename: D
authors.initials: D
authors.lastname: Menzel
authors.forename: J
authors.initials: J
authors.lastname: Schoenes
authors.forename: K
authors.initials: K
authors.lastname: Doll
authors.forename: J
authors.initials: J
authors.lastname: Röder
authors.forename: F
authors.initials: F
authors.lastname: Reinert