Gil A. Farias

Self-trapping of an electron by the surface modes

Abstract A generalized form of the Feynmans path integral method is used in order to calculate the ground-state energy and the effective mass of an electron interacting with the surface optical modes for the whole range of the coupling constant. A phase-transition-like behaviour from nearly free electron to a self-trapping electron as the coupling constant exceeds a certain critical value αc ∼3.8 is observed.

Surface plasmons on corrugated metal films

Abstract The dispersion relation for a surface plasmon, propagating across a corrugated metal film on a dielectric substrate, is obtained by the method of reduced Rayleigh equations. It is found that the surface plasmon dispersion curve has an infinite number of branches. Numerical solutions of the dispersion relation are obtained for a film, characterized by a free-electron metal dielectric function and a sinusoidal profile function.

Roughness effects in surface states of silicon

Abstract We have investigated the effects of surface roughness on the binding energies of an electron bound to an ionized impurity center located both in the silicon and in the silicon dioxide of a MOS Si(001) system. A complete form of the effective potential for the surface roughness is obtained and evaluated in terms of the mean square deviation of the surface from flatness. When the impurity is located in the oxide region the screening effects of the impurity by the electrons in the inversion layer is also taken into account. The results reported here show these effects are significant and are in satisfactory agreement with the experimental data. We have also discussed the roughness effects on the electric subband energy separations in n-type Si inversion layer. We have found that the surface roughness leads to a significant reduction of the energy separation between the lowest subbands.