Electron-Phonon Coupling at InP(110) SurfacesInvestigated by Resonant Raman Spectroscopy

Abstract

Electronic transitions at InP(110) surfaces are investigated by Surface Resonant Raman Spectroscopy (SRRS). Raman measurements of the two localized surface phonon modes at 254 and 270 cm À1 (both of A 0 -symmetry) show distinct resonances, in particular at low temperature (50 K). The deformation potential coupling between surface phonons and electronic surface states is responsible for the resonance effects. Upon cooling, a blue-shift and a significant sharpening of the relevant electronic surface transitions is revealed by Reflectance Anisotropy Spectroscopy (RAS). Characteristic structures in the surface anisotropy function at 2.80, 2.97 and 3.48 eV are assigned to critical points of the surface electronic band structure.