Spin Resolved Auger-Spectroscopy on Rb-Layers after Core-Hole Creation by Circularly Polarized VUV-Light

Circularly polarized light from BESSY with energies from 15 eV to 20 eV in normal incidence is used to excite oriented 4 p 3/2 -hole states in thick layers of Rb on Pt(111). The CVV -Auger decay of these hole states is studied in a normal-emission set-up. The preferential spin direction of the Auger-electrons has been measured to be parallel to the spin of the exciting photons near the excitation threshold and changes to be antiparallel at somewhat higher photon energies. This behaviour is consistent with an excitation varying with the photon energy and an atom-like model for the decay of the primary hole state. Thereby the two valence electrons participating in the deacy are assumed to be s -like and to be coupled to a singlet state. As the Auger-decay of the excited hole-state does not depend on the excitation, spin dependent Auger-spectroscopy opens a new method of studying excitations and unoccupied electronic states.