Degiorgi, LeonardoHunt, M. B.Ott, Hans RudolfDressel, MartinFeenstra, Bokke JohannesGrüner, GeorgeFisk, ZacharyCanfield, P.2009-09-042016-03-312009-09-042016-03-311994316440744http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-46243http://elib.uni-stuttgart.de/handle/11682/7056http://dx.doi.org/10.18419/opus-7039We have investigated the electrodynamic response of single-crystalline FeSi over a frequency range from d.c. to 10 hoch 5 cm-1. At low frequencies, we found evidence for an Anderson-Mott localization behaviour of the low-temperature optical conductivity, while at high frequencies the excitation spectrum resembles that of a conventional semiconductor. The missing spectral weight below the gap energy is redistributed around the gap edge, in disagreement with previous claims based on optical measurements.eninfo:eu-repo/semantics/openAccessEinkristall , Leitfähigkeit , Mott-Übergang , Anderson-Umwandlung530article