We calculate the linear and nonlinear optical spectra of clean Si(100)2×1 reconstructed surfaces based on the polarizable bond model. The crystal is treated as an array of pointlike polarizable dipoles in which a dipole replaces each Si-Si bond. The model incorporates the reconstruction of the surface through the local field effect. As a function of the dimer buckling of the 2×1 reconstruction, we calculate the reflectance anisotropy (linear response), and the second-harmonic generation (nonlinear response). We find that a surface with a dimer buckling of 0.6 Å qualitatively reproduces the linear and nonlinear experimental spectra. A number of physical processes, such as charge transfer in the dimer, are explored within this model and compared with experimental results.
Physical Review B
- Pub Date:
- March 2001
- Optical properties of specific thin films;
- Optical susceptibility hyperpolarizability;
- Frequency conversion;
- harmonic generation including higher-order harmonic generation