The dependence of zone axis patterns on string integrals or the number of bound states in high energy electron diffraction

Using the R-matrix dynamical theory of Reflection High-Energy Electron Diffraction (RHEED), we analyze the intensity anomalies commonly observed in RHEED rocking curves. Results for Ag(001) and Pt(111) show that the anomalies are associated with the trapping of particular components of the electron wave field inside the crystal by linear chain potential parallel to the surface. These pseudobound states correspond to minima in the total elastic flux of an ultrathin film (≤10 monolayer) and maxima in the inelastic flux. The discrete energy levels of the bound states in Ag(001) and Pt(111) are determined for the first time and the effect of such bound states on the rocking curves is discussed.

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On the relationship between projected crystal potential and the form of certain zone axis patterns in high energy electron diffraction

Philosophical Magazine ◽

10.1080/14786437708244935 ◽

1977 ◽

Vol 36 (2) ◽

pp. 279-307 ◽

Cited By ~ 18

Author(s):

M. D. Shannon ◽

J. W. Steeds

Keyword(s):

Electron Diffraction ◽

High Energy ◽

Zone Axis ◽

Energy Electron ◽

High Energy Electron ◽

Crystal Potential ◽

The Relationship

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STRUCTURAL ANALYSIS OF CRYSTAL SURFACES BY REFLECTION HIGH ENERGY ELECTRON DIFFRACTION

Surface Review and Letters ◽

10.1142/s0218625x97000481 ◽

1997 ◽

Vol 04 (03) ◽

pp. 501-511 ◽

Cited By ~ 3

Author(s):

AYAHIKO ICHIMIYA ◽

YUSUKE OHNO ◽

YOSHIMI HORIO

Keyword(s):

Electron Diffraction ◽

Surface Structure ◽

Forward Direction ◽

High Energy ◽

Zone Axis ◽

Energy Electron ◽

High Energy Electron ◽

Structure Determinations ◽

The One ◽

Diffraction Condition

For surface structure determinations by reflection high energy electron diffraction (RHEED), intensity rocking curves are analyzed through RHEED dynamical calculations. Since fast electrons are scattered dominantly in the forward direction by atoms, dynamic diffraction mainly occurs in the forward direction. By the use of this feature, it is possible to choose a diffraction condition under which electrons are diffracted mainly by lattice planes parallel to the surface, when the incident direction is chosen at a certain azimuthal angle with respect to a crystal zone axis. This diffraction condition is called the one-beam condition. Under this condition, the RHEED intensity is a function of interlayer distances and atomic densities of the surface layers. Therefore the surface normal components of the atomic positions are determined by analysis of the one-beam rocking curve using a RHEED dynamical calculation. Then, using the result of the surface normal components of atomic positions, lateral positions of the surface atoms are determined from analysis of the rocking curves at many-beam conditions, where the direction of the incident beam is chosen along a certain crystal zone axis. An example of the surface structure determination of a Si(111) surface at high temperatures is reported. We discuss effects of terraces and antiphase domains of surfaces in structure determinations by RHEED.

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Crystal Surface Symmetry from Zone-Axis Patterns in Reflection High-Energy-Electron Diffraction

Physical Review Letters ◽

10.1103/physrevlett.53.2125 ◽

1984 ◽

Vol 53 (22) ◽

pp. 2125-2128 ◽

Cited By ~ 11

Author(s):

M. D. Shannon ◽

J. A. Eades ◽

M. E. Meichle ◽

P. S. Turner ◽

B. F. Buxton

Keyword(s):

Electron Diffraction ◽

Crystal Surface ◽

High Energy ◽

Zone Axis ◽

Energy Electron ◽

High Energy Electron

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Kinematic Approximations in TED and RHEED Analysis of Reconstructed Surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135587 ◽

1990 ◽

Vol 48 (2) ◽

pp. 396-397

Author(s):

L. -M. Peng ◽

M. J. Whelan

Keyword(s):

Electron Diffraction ◽

Kinematic Analysis ◽

Incident Beam ◽

High Energy ◽

Energy Electron ◽

Great Success ◽

High Energy Electron ◽

Kinematic Approximation ◽

Reconstructed Surfaces

In recent years there has been a trend in the structure determination of reconstructed surfaces to use high energy electron diffraction techniques, and to employ a kinematic approximation in analyzing the intensities of surface superlattice reflections. Experimentally this is motivated by the great success of the determination of the dimer adatom stacking fault (DAS) structure of the Si(111) 7 × 7 reconstructed surface.While in the case of transmission electron diffraction (TED) the validity of the kinematic approximation has been examined by using multislice calculations for Si and certain incident beam directions, far less has been done in the reflection high energy electron diffraction (RHEED) case. In this paper we aim to provide a thorough Bloch wave analysis of the various diffraction processes involved, and to set criteria on the validity for the kinematic analysis of the intensities of the surface superlattice reflections.The validity of the kinematic analysis, being common to both the TED and RHEED case, relies primarily on two underlying observations, namely (l)the surface superlattice scattering in the selvedge is kinematically dominating, and (2)the superlattice diffracted beams are uncoupled from the fundamental diffracted beams within the bulk.

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