point defect


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Related to point defect: Frenkel defect, line defect

point defect

[′pȯint di‚fekt]
(crystallography)
A departure from crystal symmetry which affects only one, or, in some cases, two lattice sites.
References in periodicals archive ?
Another difference between the models is that common liquid crystal "defects" (such as "point defects" and "disclination lines") are singularities of the director field in the Oseen-Frank model, whereas in the Landau-de Gennes model, these have a small but finite "core size" and the associated tensor field Q remains smooth throughout a neighborhood of such a defect.
Up to now, a large number of experimental and theoretical studies have been devoted to the characterization of the structure of point defects in [alpha]-quartz [1-3].
By creating point defects the periodicity of the crystal is broken and it allows the propagation of light into the band gap.
The formation energy of various single point defects in W is summarized in Table 2, and the results are in good agreement with other calculation results [1, 20, 21].
Materials under radiation of high-energy particles and severe plastic deformation will develop point defects or defect clusters, which may subsequently evolve into microstructural flaws, such as voids, stacking fault tetrahedra, dislocation loops, or solute segregation [1-6].
This analogy describes contact mode AFMs, specifically point defect resolution--far trickier imaging than lattice resolution.
While avoiding overlap with other papers in this volume, this article summarizes results from: 1) early work on crystallization as a method of purification, in contributions to sugar chemistry, and in solution growth of large crystals; 2) the NBS/ARPA Program of research on crystal growth and characterization; 3) the NBS Free-Radical Research Program; 4) the XRCD method as a direct path to relative atomic mass data and the fundamental physical constants; 5) the dynamical theory of x-ray diffraction; and 6) symmetry considerations such as are involved in the influence on crystals of mechanical stress or fields, and of point defect motion.
MacDonald, "The history of the Point Defect Model for the passive state: A brief review of film growth aspects," Electrochimica Acta, vol.
Fang, "Interaction energy of dislocation and point defect in bcc iron," Radiation Effects and Defects in Solids, vol.
In this paper, we perform the first-principles calculation based on the density functional theory (DFT) to investigate the effect of intrinsic point defect on the magnetic properties of ZnO nanowire.
The combined effects of these two phenomena are shown in Figures 4(a) and 4(b), where the temporal profiles of the average point defect net-production rate in layer [alpha], [bar.[[PI].sup.([alpha])]] and layer [beta], [bar.[[PI].sup.([beta])]] are reported, respectively.