Bulk-plasmon dispersion relation and linewidthin beryllium by inelastic x-ray scattering

TIRAO, G.; C. CUSATIS; G. STUTZ

LNLS, Campinas

Congreso; XIII Reunión Anual de Usuarios del LNLS; 2003

Inelastic x-ray scattering spectroscopy (IXSS) based on synchrotron radiation sources is a well established technique to investigate both individual and collective eV electronic excitations in the condensed matter. In an inelastic scattering process energy w and momentum q are trasferred by the x-ray probe to the scattering system. The differential cross-section in first order is proportional to the so-called dynamic structure factor S(q,w) of the scattering electron. This factor is related to the dielectric function e(q,w) and to the response of the electron system to an external pertubation of frecuency w and wave-vector q. The elementary excitation appeares in the x-ray energy-loss spectra as a pronounced peak, centeder at the energy w with a characteristic intrinsic width. In this work we present an experimental study of plasmon excitation in Be by means of IXSS.