  With high-resolution photoemission spectroscopy measurements, the density of
states (DOS) near the Fermi level ($E_\mathrm{F}$) of double perovskite
Sr$_2$FeMoO$_6$ having different degrees of Fe/Mo antisite disorder has been
investigated with varying temperature. The DOS near $E_\mathrm{F}$ showed a
systematic depletion with increasing degree of disorder, and recovered with
increasing temperature. Altshuler-Aronov (AA) theory of disordered metals well
explains the dependences of the experimental results. Scaling analysis of the
spectra provides experimental indication for the functional form of the AA DOS
singularity.
