Adatoms on Si(111) and Ge(111) surfaces

Robert D. Meade, David Vanderbilt

Research output: Contribution to journalArticle

201 Citations (Scopus)

Abstract

First-principles calculations of energy and stress are performed on adatom-covered Si(111) and Ge(111) surfaces. The presence of adatoms is found to lower the surface energy and cause a large change in surface stress. While the 1×1 surfaces are under a weak compressive stress, the 3×3 and 2×2 adatom-covered surfaces are under a strong tensile stress. Calculations at high plane-wave cutoff unambiguously identify the 2×2 top-site geometry as the energetically preferred adatom configuration. Relaxed geometries are presented and compared with x-ray structural measurements of adatoms in the Si(111)-7×7 structure. Vibrational mode frequencies and eigenvectors of the adatom unit are determined from a comprehensive set of frozen-phonon calculations for the Si 2×2 surface; we find two symmetric modes that are strongly localized at the surface, in agreement with electron-energy-loss spectroscopy measurements. It is found that the 2×2 adatom-covered surfaces have three surface bands, and the dispersion relations are calculated along symmetry directions in the surface Brillouin zone. The surface band structures are in good agreement with angle-resolved photoelectron-spectroscopy data for the 7×7-Si(111) surface.

Original languageEnglish (US)
Pages (from-to)3905-3913
Number of pages9
JournalPhysical Review B
Volume40
Issue number6
DOIs
StatePublished - Jan 1 1989
Externally publishedYes

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adatoms
geometry
tensile stress
Brillouin zones
surface energy
vibration mode
eigenvectors
plane waves
cut-off
energy dissipation
photoelectron spectroscopy
electron energy
causes
symmetry
configurations

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Cite this

Meade, Robert D. ; Vanderbilt, David. / Adatoms on Si(111) and Ge(111) surfaces. In: Physical Review B. 1989 ; Vol. 40, No. 6. pp. 3905-3913.
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Adatoms on Si(111) and Ge(111) surfaces. / Meade, Robert D.; Vanderbilt, David.

In: Physical Review B, Vol. 40, No. 6, 01.01.1989, p. 3905-3913.

Research output: Contribution to journalArticle

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