TEMPERATURE AND SUBSTITUTION DEPENDENCE OF THE PHOTOEMISSION SPECTRA OF FESI

We have studied the effect of varying temperature and Co substitution on the low-energy electronic structure of FeSi by photoemission spectr oscopy. We have observed that the density of states (DOS) of FeSi is r educed at low temperatures over a wide energy range of similar to 50 m eV below the Fermi level (E-F), which is the energy scale observed by the magnetic, transport and optical measurements. The reduced DOS is c ompletely recovered with increasing temperature but only partly, i.e., predominantly near E-F, With Co substitution, again consistent with t he transport properties. [S0163-1829(98)00428-7].