Measurement of Surface-Plasmon Dispersion in Aluminum by Inelastic Low-Energy Electron Diffraction

Abstract

Analysis of the inelastic differential cross section for low-energy ($10\ensuremath{\lesssim}E\ensuremath{\lesssim}{10}^{3}$ eV) electron scattering from single-crystal solid surfaces permits the determination of the dispersion relation of the excitations created by the electron. With energies measured in eV and momenta parallel to the surface, ${p}_{\ensuremath{\parallel}}$, in ${\mathrm{\AA{}}}^{\ensuremath{-}1}$, the surface-plasmon dispersion for Al(111) is $\ensuremath{\hbar}{\ensuremath{\omega}}_{s}({p}_{\ensuremath{\parallel}})=10.1\ensuremath{-}0.7{p}_{\ensuremath{\parallel}}+10{{p}_{\ensuremath{\parallel}}}^{2}$ and its damping is ${\ensuremath{\Gamma}}_{s}({p}_{\ensuremath{\parallel}})=0.9+0.7{p}_{\ensuremath{\parallel}}$.