COMPOSITION DEPENDENCE OF THE POSITRON ANNIHILATION IN Zn1-xBexSe

2005 ◽  
Vol 19 (17) ◽  
pp. 849-860
Author(s):  
F. BENKABOU
Keyword(s):  
Positron Annihilation ◽  
Energy Gap ◽  
Momentum Density ◽  
Annihilation Radiation ◽  
Virtual Crystal Approximation ◽  
Zinc Blende ◽  
Electron Positron ◽  
Wide Energy ◽  
Pseudo Potential ◽  
Zinc Blende Structure

In order to clarify the electronic and optical properties of wide-energy gap zinc-blende structure ZnSe , BeSe and their alloys, a simple pseudo-potential scheme (EPM), within an affective potential the virtual crystal approximation (VCA) which incorporates compositional disorder as an effective potential are presented. Angular correlation of positron annihilation radiation (ACPAR) along different crystallographic directions in Zn 1-x Be x Se are calculated. We observe that the electron-positron momentum density increases rapidly with increasing Beryllium content.

scholarly journals Calculation of the Doppler broadening of the electron-positron annihilation radiation in defect-free bulk materials

2000 ◽  
Vol 61 (15) ◽  
pp. 10092-10099 ◽  
Author(s):  
V. J. Ghosh ◽  
M. Alatalo ◽  
P. Asoka-Kumar ◽  
B. Nielsen ◽  
K. G. Lynn ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Annihilation Radiation ◽  
Doppler Broadening ◽  
Bulk Materials ◽  
Electron Positron Annihilation ◽  
Electron Positron

Doppler broadening measurements of the electron-positron annihilation radiation in nanocrystalline ZrO2

2005 ◽  
Vol 40 (19) ◽  
pp. 5265-5268 ◽  
Author(s):  
M. Chakrabarti ◽  
D. Bhowmick ◽  
A. Sarkar ◽  
S. Chattopadhyay ◽  
S. Dechoudhury ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Annihilation Radiation ◽  
Doppler Broadening ◽  
Electron Positron Annihilation ◽  
Electron Positron

INTEGRAL results on the electron-positron annihilation radiation and X-ray & Gamma-ray diffuse emission of the Milky Way

2020 ◽  
Vol 90 ◽  
pp. 101548 ◽  
Author(s):  
Eugene Churazov ◽  
Laurent Bouchet ◽  
Pierre Jean ◽  
Elisabeth Jourdain ◽  
Jürgen Knödlseder ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Milky Way ◽  
Gamma Ray ◽  
Annihilation Radiation ◽  
Diffuse Emission ◽  
X Ray ◽  
Electron Positron Annihilation ◽  
Electron Positron

ELASTIC CONSTANTS AND ACOUSTIC WAVE VELOCITIES IN Cd1-xZnxTe MIXED CRYSTALS

2008 ◽  
Vol 22 (12) ◽  
pp. 1221-1229 ◽  
Author(s):  
N. BOUARISSA ◽  
Y. ATIK
Keyword(s):  
Acoustic Wave ◽  
Elastic Constants ◽  
Mixed Crystals ◽  
Bulk Acoustic Wave ◽  
Virtual Crystal Approximation ◽  
Wave Speeds ◽  
Wave Velocities ◽  
Zinc Blende ◽  
Compositional Disorder ◽  
Zinc Blende Structure

Based on the pseudopotential scheme under the virtual crystal approximation that takes into account the effect of compositional disorder combined with the bond-orbital model of Harrison, the results of calculations of elastic constants and surface and bulk acoustic wave speeds of Cd 1-x Zn x Te mixed crystals in the zinc-blende structure are presented. The agreement between our results and known data, which are only available for CdTe and ZnTe is found to be reasonable.

a-axis-projected electron-positron-momentum density and positron-annihilation spectra inYBa2Cu3O7−x

1994 ◽  
Vol 50 (9) ◽  
pp. 6408-6415 ◽  
Author(s):  
R. Pankaluoto ◽  
A. Bansil ◽  
L. C. Smedskjaer ◽  
P. E. Mijnarends
Keyword(s):  
Positron Annihilation ◽  
Momentum Density ◽  
Electron Positron

scholarly journals Measuring electron-positron annihilation radiation from laser plasma interactions

2012 ◽  
Vol 83 (10) ◽  
pp. 10E113 ◽  
Author(s):  
Hui Chen ◽  
R. Tommasini ◽  
J. Seely ◽  
C. I. Szabo ◽  
U. Feldman ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Laser Plasma ◽  
Annihilation Radiation ◽  
Plasma Interactions ◽  
Laser Plasma Interactions ◽  
Electron Positron Annihilation ◽  
Electron Positron

Point Defects in γ-Irradiated Germanium: High- and Low- Momentum Positron Annihilation Study Before and After n-p-Conversion

2009 ◽  
Vol 156-158 ◽  
pp. 455-460
Author(s):  
N.Yu. Arutyunov ◽  
Valentin V. Emtsev ◽  
Reinhard Krause-Rehberg
Keyword(s):  
Electron Density ◽  
Impurity Atom ◽  
Momentum Density ◽  
Annihilation Radiation ◽  
High Momentum ◽  
Group V ◽  
Electron Momentum ◽  
Electron Positron ◽  
Before And After ◽  
Positron Annihilation Study

The electron momentum distribution and microstructure of centers incorporating a vacancy (vacancies) and a group-V-impurity atom (P, As, Sb, or Bi) in oxygen-lean n-Ge crystals have been investigated by means of the angular correlation of the annihilation radiation (ACAR). The vacancy-group-V-impurity atom complexes have been induced by irradiation with 60Co γ – rays at Tirr. ≈ 280K. A split between the intensities of the high-momentum emission of the annihilation radiation measured before and after n-p-conversion has been revealed for the complexes containing smaller ion cores (P, As) and the larger ones (Sb, Bi), respectively. After n-p-conversion the electron density decreases slightly (but markedly) around the positron localized at the vacancy complexes incorporating P, Sb, and Bi impurity atom. This decrease is accompanied by a lessening of intensity of the high-momentum emission of the annihilation radiation thus bringing in a direct evidence of a multi-vacancy structure of the vacancy-group-V-impurity atom complexes after n-p-conversion; the electron density was found to be affected by the localized deep acceptor states related to these centers. The relaxation inward open volume is a common feature which is pronounced for As-containing complexes. Subvalent band states are suggested to contribute the high-momentum annihilation most markedly. The electron momentum density around the positron is due to rather by the elemental specificity of the surrounding atoms than by changes of the electron-positron many-body interaction in the vacancy-group-V-impurity atom complexes.

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