Deceleration of charged particles in a two-dimensional electron gas with impurity states of electrons

Differential cross-section of inelastic scattering and loss function of fast charged particles in a two-dimensional electron gas are calculated at low temperatures, taking into account the localization of electrons at impurity atoms. The contribution of one-particle and collective excitations of the electron gas to the scattering cross-section and loss function is considered. One-particle excitations are manifested in the existence of a threshold of scattering cross-section and loss function, associated with a transition of localized electrons to the conduction band. Localization of electrons leads to a decrease in the frequency of two-dimensional plasmons. Consequently, the plasma loss lines in the energy spectrum of electrons passing through a two-dimensional electron gas are displaced towards lower frequencies and are broadened. Numerical estimates are obtained for the inversion layer at the boundary between silicon and silicon dioxide. (C) 1999 American Institute of Physics. [S1063-777X(99)01006-3].