  In this paper, we study several structural models of amorphous silicon, and
discuss structural and electronic features common to all. We note spatial
correlations between short bonds, and similar correlations between long bonds.
Such effects persist under a first principles relaxation of the system and at
finite temperature. Next we explore the nature of the band tail states and find
the states to possess a filamentary structure. We detail correlations between
local geometry and the band tails.
