Perturbation theory of diffuse RHEED applied to rough surfaces: Comparison with supercell calculations

Autor(en): Korte, U
McCoy, JM
Maksym, PA
MeyerEhmsen, G
Stichwörter: DYNAMICAL DIFFRACTION; ENERGY ELECTRON-DIFFRACTION; INTENSITIES; Materials Science; Materials Science, Multidisciplinary; Physics; Physics, Applied; Physics, Condensed Matter; PT(111); SCATTERING; STEPPED SURFACES; TRANSITION
Erscheinungsdatum: 1996
Volumen: 54
Ausgabe: 3
Startseite: 2121
Seitenende: 2137
We present a thorough investigation of the conditions under which the perturbation theory of diffuse RHEED [Phys. Rev. B 48, 8345 (1993)] (diffuse scattering treated as the transition between states in thr periodic part of the potential) can be used for the evaluation of experimental diffuse scattering data from occupational disorder (e.g., steps). Such an investigation is desirable because this method solves the configuration problem, i.e., the presence of many statistically varying disorder configurations, within the scope of a dynamical theory. We have carried out comparisons with rigorous supercell calculations for streak profiles due to bilayer steps upon a Si(100) surface. The general trend of the results obtained is supported by some simple analytical considerations. An analytical expression is derived that predicts the approximate error made in the perturbation approach compared to an exact treatment. Besides general features, such as defect concentration and the strength of the atomic potential, the important structural quantity that determines the quality of the perturbation approach is the correlation length of the disorder along the incident beam azimuth. If this length is sufficiently small, perturbation theory works well and is independent of the diffraction condition. Otherwise, the applicability of perturbation theory depends on the diffraction condition. The physics behind conditions suitable for perturbation theory to work, as well as their experimental realization, is discussed.
ISSN: 10980121
DOI: 10.1103/PhysRevB.54.2121

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