scholarly journals Comparison with experimental data of different theoretical approaches to high-energy electron bremsstrahlung including quantum coherence effects

2021 ◽  
Vol 104 (9) ◽  
Author(s):  
A. Mangiarotti ◽  
P. Sona ◽  
U. I. Uggerhøj
Keyword(s):  
Experimental Data ◽  
Quantum Coherence ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Theoretical Approaches ◽  
Electron Bremsstrahlung ◽  
Coherence Effects ◽  
Quantum Coherence Effects ◽  
Comparison With Experimental Data

Computer studies on reflection high-energy electron diffraction from the growing surface of Ge(001)

2013 ◽  
Vol 46 (4) ◽  
pp. 1024-1030 ◽  
Author(s):  
Zbigniew Mitura
Keyword(s):  
Experimental Data ◽  
Electron Diffraction ◽  
High Energy ◽  
Bloch Wave ◽  
Energy Electron ◽  
High Energy Electron ◽  
Homoepitaxial Growth ◽  
Scattering Potential ◽  
Computer Studies ◽  
Quantitative Explanation

The results of calculations of reflection high-energy electron diffraction intensities, measured at different stages of the homoepitaxial growth of Ge(001), are described. A two-dimensional Bloch wave approach was used in calculations of the Schrödinger equation with a one-dimensional potential. The proportional model was used for partially filled layers,i.e.the scattering potential was taken to be proportional to the coverage and the potential of the fully filled layer. Using such an approach, it was shown that it is possible to obtain valuable information for the analysis of experimental data. The results of these calculations were compared with data for off-symmetry azimuths from the literature, and satisfactory agreement between the theoretical and experimental data was found. Also assessed was whether developing more advanced models (i.e.going beyond the proportional model), to make a more detailed account of the diffuse scattering, might be important in achieving a fully quantitative explanation of the experimental data.

Kinematic Approximations in TED and RHEED Analysis of Reconstructed Surfaces

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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