Evidence for itineracy in the anticipated Kondo insulator FeSi: a quantitative determination of the band renormalization.
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.
Klein
M
M
Universität Würzburg, Experimentelle Physik II, Am Hubland, D-97074 Würzburg, Germany.
Zur
D
D
Menzel
D
D
Schoenes
J
J
Doll
K
K
Röder
J
J
Reinert
F
F