Yanguo WANG
,
Hongrong LIU
,
Canying CAI
,
Qibing YANG
材料科学技术（英文）
Based on the electron dynamic diffraction, phase shift of the exit wave function vs misorientation of the incident electron beam from the exact zone axis has been calculated for the [001] oriented copper. The result shows that the peak of phase shift is the maximum at the atom position as the electron beam along the exact [001] zone axis, and the peak value of phase shift decreases as increases of the misorientation. At small misorientation, i:e. less than 5 degree, change of the phase shift is minimal. The peak value of phase shift decreases significantly when the incident beam deviates form the zone axis over 10 degree and the exit wave has a planar configuration as the misoriention angle arrives ～17 degree. The effect of this phase shift characteristics on the information extracted from the hologram has also been considered.
关键词:
Canying CAI
,
Qibin YANG
,
Hongrong LIU
,
Yanguo WANG
材料科学技术（英文）
The exit wave function including zero and high order Laue zones has been simulated by both multi-slice method and electron dynamic diffraction analytical expression. Coincidence of the simulations by these two methods was achieved. The calculated results showed that the exit wave function highly dominated by zero order Laue zone, while high order ones modify the exit wave function to some extent depending on the situation. High order Laue zone effects become important for the following cases: sample consists of light elements, the thickness is very thin, lattice planar spacing perpendicular to the direction of the incident beam is large, and the electron beam has long wavelength. In these cases the exit wave function should be corrected by adding high order Laue zone effects. The analytical expression is effective and convenient for dealing with high order Laue zone effects.
关键词:
Electron dynamical diffraction
,
null
,
null
Canying CAI
,
Qibin YANG
,
Hongrong LIU
材料科学技术（英文）
Assuming that the wave function , the Schrodinger equation can be written as . Neglecting the last two terms, an analytical expression of electron dynamical diffraction was derived by Qibin YANG et al. In this paper, the analytical expression is modified by further considering the second-order differential term . When the accelerating voltage is not very high, or the sample is not very thin, the reciprocal vector ɡ is large, the modification of the second-order differential is necessary; otherwise it can be neglected.
关键词:
Electron dynamical diffraction
,
null
