Ultrafast band-structure variations induced by fast Au ions in BeO

Auger-electron spectra associated with Be atoms in the pure metal lattice and in an oxide have been investigated for 1.8 MeV/u 129Au41+ ions and 2.7 keV primary electrons. The excitation and local energy transfer by such fast primary particles in solids is dominated by electronic processes. The electron-induced spectrum is compared to calculated band-structure results and it is relatively well understood. For the heavy-ion case, however, we observe a significant variation of the Auger electron spectrum, related to a variation of the electronic band structure. This spectrum points to a formation of a metal-like meta-stable electronic density of states.