  Effects of electron correlation in FeSi are studied in terms of the two-band
Hubbard model with the density of states obtained from the band calculation.
Using the self-consistent second-order perturbation theory combined with the
local approximation, the correlation effects are investigated on the density of
states and the optical conductivity spectrum, which are found to reproduce the
experiments done by Damascelli et al. semiquantitatively. It is also found that
the peak at the gap edge shifts to lower energy region by correlation effects,
as is seen in the experiments.
