Optical reflectivity of the Si(111)-(2x1)surface--the role of theelectron-hole interaction
We calculate the optical reflectivity of the Si(111)-(2x1) surface from first principles. To this end, we first calculate the quasiparticle band structure of the surface within the GW approximation for the electronic self energy. The band structure exhibits two surface bands inside the fundamental bulk band gap. Thereafter the electron-hole interaction is computed for transitions between the relevant bands, the Bethe-Salpeter equation for coupled electron-hole excitations is solved and the optical response is evaluated. In the energy range below the fundamental bulk band gap, the reflectivity spectrum is dominated by a surface exciton at 0.43 eV with an excitonic binding energy of 0.26 eV. Our calculated spectrum is in very good agreement with experimental data from differential reflectivity spectroscopy.
- Research Organization:
- Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Basic EnergySciences. Materials Sciences Division; National Science Foundation GrantDMR-9520554; Deutsche Forschungsgemeinschaft GrantRo-1318/2-1
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 878112
- Report Number(s):
- LBNL--48752; BnR: KC0202030
- Journal Information:
- Physica Status Solidi (A), Journal Name: Physica Status Solidi (A) Journal Issue: 1 Vol. 175
- Country of Publication:
- United States
- Language:
- English
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