Observation of circular dichroism in angular distribution of the valence band photoelectron from Si(001) in UPS region

Circular dichroism in angular distribution was observed for the valence band photoelectron from nonmagnetic and nonchiral material Si(001) with the incident photon energy in UPS region. The obtained two-dimensional angular distributions are to a certain extent consistent with an analysis of simple electronic dipole transition. Calculated angular distributions based on highly accurate one-step model showed better agreement considering photoelectron diffraction effect.