Ultrafast Electronic Processes in an Insulator: the Be and O Sites in BeO

The short-time dynamics of amorphous beryllium oxide (a-BeO) has been investigated for electronic excitation/ionization by fast incident electrons, as well as by Ar, Ar, Xe, and Xe ions at velocities of 6% to 10% the speed of light. Site specific Augerelectron spectra induced by fast heavy ions are the central point of this investigation. Electron induced Auger spectra serve as a reference and electron-energy loss (EELS) spectroscopy as well as resonant inelastic x-ray scattering (RIXS) are invoked for quantitative understanding. For the heavy-ion case, we observe strong variations in the corresponding spectral distributions of Be-K and O-K Auger lines. These are related to local changes of the electron density, of the electron temperature and even of the electronic band structure of BeO on a femtosecond time scale after the passage of highly charged heavy ions. PACS numbers: 79.20.Rf, 71.20.Ps, 31.70.Hq, 32.80.Hd, 61.80.Jh