Xiaohong YAN
,
Jianwen DING
,
Qibin YANG
,
Bruno Iochum
材料科学技术（英文）
We present a new series of two-dimensional decagonal tilings which are connected with each in five transformation rules. In this case, a real-space renormalization group scheme is developed to study physical properties of the decagonal systems in terms of Green's function theory.
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
Qiuxiang LIU
,
Yuanming WANG
,
Qibin YANG
,
Xiaohong YAN
材料科学技术（英文）
Based on a definitely integral formula, an expression of calculating atomic potential distribution function U(r) in a unit cell is derived as follows: Making use of this expression to calculate the phase grating in high resolution image simulation can greatly reduce the calculating time. In this paper, the derivation of the expression is introduced, and then the computer routine is explained in details. Finally the potential projection map of Mg44Rh7 along [001] direction is shown as an illustration. All operations are carried out in real space, so we call the calculation method as the real space method.
关键词:
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
