  We have performed temperature (T) - dependent laser-photoemission
spectroscopy of antiferromagnetic (AF) superconductor ErNi2B2C to study the
electronic-structure evolution reflecting the interplay between
antiferromagnetism and superconductivity. The spectra at the superconducting
(SC) phase show a very broad spectral shape. T-dependent SC gap shows a sudden
deviation from the BCS prediction just below TN. This observation can be well
explained by the theoretical model and thus represents characteristic bulk
electronic structure of the AF SC phase for the first time.
