Shift of surface-plasmon energy across the phase transitions of silicon reconstructed structures for several crystal planes

Abstract

By electron-energy-loss spectroscopy, energy shifts of the surface plasmon were observed across the phase transitions for several reconstructed structures of silicon surfaces. The surface-plasmon energy shifts by 1.0-1.6 eV, depending on the phase transitions for Si(111) and Si(110) surfaces. A bulk plasmon and other peaks associated with the interband transitions between localized electronic states did not exhibit any notable change. For the Si(100) surface, no shift occurred, corresponding to the nonexistence of a phase transition. The energy shift of the surface plasmon was found to reflect the surface structure change. Two kinds of qualitative interpretation of this shift are presented. One is a change of dielectric function and the other is a change of the electronic density distribution at the surface due to the phase transition.