Abstract
We present a first-principles linear-response study of the phonon spectrum and dipole activity of the Si(111)2×1 surface. Our results are in good agreement with the experimental He-scattering results for the acoustic modes, as well as the electron-energy-loss data for the optical modes. We clarify a current controversy on the assignment of the electron-energy-loss peak at 56 meV. We find that the dominant contribution to the loss peak is anisotropic and arises from a longitudinal-optical vibration of the surface chains. However, a small but non-negligible isotropic contribution comes from subsurface modes polarized perpendicular to the surface.
Original language | English (US) |
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Pages (from-to) | 8930-8933 |
Number of pages | 4 |
Journal | Physical Review B |
Volume | 43 |
Issue number | 11 |
DOIs | |
State | Published - 1991 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics