Spin selectivity by Auger-PhotoElectron coincidence spectroscopy

The M3M4,5M4,5 Auger transition from a Cu(111) surface is studied using Angular Resolved Auger-PhotoElectron Coincidence Spectroscopy (AR-APECS). In the experiment two different geometrical configurations of the electron analyzers allow us to sample different emission angles of the ejected electrons leading to different weights of the singlet and triplet contributions in the studied transition. The experimental spectra are modeled within a two-step approach using the Cini theory for the closed band case so as to properly consider the spin-orbit interaction and the hole-hole correlation energy. Ingredients for the theory, like density of states, are obtained fully ab-initio in the framework of density functional theory by performing all-electron calculations. The obtained results confirm the recently discovered selectivity of AR-APECS in the final spin-state.