Angular distribution and spin polarization of Auger-electrons from a potassium (110) surface

The calculations of the spin-polarized M2.3VV Auger-electron emission follo wing a core-hole excitation by circularly polarized photons from a potassiu m (110) surface has been performed. The angular distribution of the Auger-e lectron intensity is discussed and different factors determining the spin p olarization of Auger-electrons are examined. It has been shown that the str ong angular dependence of the Auger-electron spin polarization, predicted b y the atomic model (where only the (ss) two-hole final state is considered) , is substantially suppressed by contributions from the p- and d-states in the valence band of potassium crystal. This almost isotropic Auger emission can be significantly modified (particularly with respect to the angular di stribution of the intensity) if the diffraction of the outgoing Auger wave on the atoms of the crystal is taken into account. In order to achieve a qu antitative agreement of the calculated results with the available experimen tal data, the theoretical models should be improved to be valid for the acc urate treatment of the scattering processes at small kinetic energies of th e excited electrons.