Variations in the lifetime of 3d hole states in ultrathin Fe films grown on Cu(100) deduced from the LMM Auger spectra of Fe

The Fe LMM Auger and Auger vacancy satellite spectra of ultrathin Fe films grown on Cu(100) have been measured using photon excitation energies above and below the L-2 ionisation edge, and in coincidence with the Fe 2p(3/2) and Fe 2p(1/2) photoelectrons. A comparison of the relative intensities of the satellites and main Auger transitions indicates that the M-4,M-5 holes of L3M4,5 double hole states are localised for longer than the L-3 lifetime for the 0.3 and 10 ML coverages but have a lifetime comparable to that of L3 holes for the 1 ML coverage. The results for the 1 ML coverage are supported by the results of the coincidence experiments. The reasons for the variation in the lifetime Of M-4,M-5 holes are discussed in terms of changes in the number of Fe-Fe neighbours and the density of states at the Fermi energy in these systems.