Angular distribution and spin polarization of Auger electrons following photoionization by polarized x-rays

Abstract

Due to the absorption of circularly polarized light the spin of a core hole has a preferred value. The difference of the radial matrix elements for the two photoelectron channels and the energy dependence of the radial matrix elements has an important influence on the spin polarization. In the Auger transition process this spin polarization can be transferred to the Auger electron. The degree of the spin polarization of the Auger electrons mainly is determined by the core hole spin and by the contribution of the exchange integral in the auger matrix element. Furthermore it can be influenced by an exchange splitting of the core level due to an atomic magnetic moment and by a spin polarization of the density of states in the final state at the Auger electron energy. The transition probability and the spin polarization is calculated as well for the angle integrated as for the angle resolved Auger electron intensity for an atom of a bulk system to get the primary wave of a diffraction process of the Auger electron at the surrounding atoms. Results are presented for LMM Auger electrons of Ni. The influence of the exchange-splitting of the core levels involved in the Auger process is investigated for the LMM transition of Fe.