Abstract
Bismuth adsorbs on the Si(001)-(1 x 2) surface in the form of rows of
dimers. Missing-dimer lines (MDLs) are created perpendicularly every n
units, leading to (2 x n) periodicity. Depending on the coverage, n can
vary from 12 to 5. We investigated by grazing incidence x-ray
diffraction the (2 x n) structure, with n = 6.45. The disorder in the
MDL periodicity, as well as the defects along the MDL, reduce
considerably the correlation length of the reconstructed domains. As a
consequence, the integrated intensity of each reflection must be
corrected, evaluating the trace of the resolution function across the
diffraction node. The structural refinement, based on the as-derived
intensities, provides the Bi dimer bond length (3.11 Angstrom) the Si
atom positions (bulklike), and the height of the Pi plane with respect
to Si (1.88 Angstrom). In addition, we give evidence that the dimers are
displaced along the row from ideal positions towards the MDL (from 0.15
to 0.50 Angstrom). Last, the diffraction profiles are calculated, on the
basis of a probability distribution of (2 x n) cells (n = 6, 7, 1),
using the phase-matrix method. The average positions of the fractional
peaks are related to the concentration of each type of cell. The width
and the intensity of the second order peaks, compared to those of the
first order peaks, allow us to account for the aggregation tendency.
Lingua originale | English |
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pagine (da-a) | 1935-1951 |
Numero di pagine | 17 |
Rivista | JOURNAL OF PHYSICS. CONDENSED MATTER |
Volume | 11 |
DOI | |
Stato di pubblicazione | Pubblicato - 1999 |
Keywords
- BI
- GRAPHITE-INTERCALATION COMPOUNDS
- ORIGIN
- RAY-DIFFRACTION
- SI(001)
- SI(100)