Surface phonons and dipole activity of Si(111)2×1 from ab initio calculations

F. Ancilotto, A. Selloni, W. Andreoni, S. Baroni, R. Car, M. Parrinello

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


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 languageEnglish (US)
Pages (from-to)8930-8933
Number of pages4
JournalPhysical Review B
Issue number11
StatePublished - 1991
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics


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