Optical gap between dangling-bond states of a single-domain diamond C(111)- by reflectance anisotropy spectroscopyG. Bussetti1, C. Goletti1, P. Chiaradia1 and T. Derry2
1 Dipartimento di Fisica and CNISM, Università di Roma "Tor Vergata" - Roma, Italy
2 School of Physics and Centre of Excellence in Strong Materials, University of the Witwatersrand - Johannesburg, Wits 2050, South Africa
received 19 April 2007; accepted in final form 6 July 2007; published September 2007
published online 30 July 2007
The optical gap between dangling-bond states has been measured on a single-domain diamond C(111)- surface. The experimental result is 1.47 eV. Such a large surface gap (even larger if excitonic effects are considered) so far has not been obtained by state-of-the-art band calculations and its physical origin is still not elucidated. The experimental result suggests a strong electron-phonon interaction in this surface. The renormalization of the bare electronic transition energy by electron-phonon interaction provides a clue to solve the apparent disagreement between theory and experiment.
78.68.+m - Optical properties of surfaces.
73.20.At - Surface states, band structure, electron density of states.
68.35.Bs - Structure of clean surfaces (reconstruction).
© Europhysics Letters Association 2007