Electron-phonon coupling at InP(110) surfaces investigated by Resonant Raman Spectroscopy

Electronic transitions at InP(110) surfaces are investigated by Surface Res onant Raman Spectroscopy (SRRS). Raman measurements of thr two localized su rface phonon modes at 254 and 270 cm(-1) (both of A'-symmetry) show distinc t resonances, in particular at low temperature (50 K). The deformation pote ntial coupling between surface phonons and electronic surface states is res ponsible for the resonance effects. Upon cooling, a blue-shift and a signif icant 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.