We have identified stable fourfold coordinated vacancy clusters Vn 3 n 18 in Si using a combination of metropolis Monte Carlo, tight-binding molecular-dynamics, and density-functional theory calculations. Our calculations show that the small vacancy defects exclusively favor fourfold coordination thermodynamically rather than hexagonal ringlike structure formation, which has widely been adapted...

in this article, we suggested a novel design of polarization splitter based on coupler waveguide on inp substrate at 1.55mm wavelength. photonic crystal structure is consisted of two dimensional (2d) air holes embedded in inp/ingaasp material with an effective refractive index of 3.2634 which is arranged in a hexagonal lattice. the photonic band gap (pbg) of this structure is determined using t...

Oxide ion conductors are important materials with a range of technological applications and are currently used as electrolytes for solid oxide fuel cells and solid oxide electrolyzer cells. Here we report the crystal structure and electrical properties of the hexagonal perovskite derivative Ba3MoNbO8.5. Ba3MoNbO8.5 crystallizes in a hybrid of the 9R hexagonal perovskite and palmierite structure...

Two-dimensional (2-D) spatially varying convolutional filters for three-dimensional (3-D) depth extrapolation are efficiently designed and implemented by using McClellan transformations. Although efficient, McClellan transformations only approximate circularly symmetric depth extrapolation filters. The accuracy of the extrapolation filters can be increased only at an increase in the computation...

Hexagonal hierarchical microtubular structures are produced by diphenylalanine self-assembly and the ratio of the relative humidity in the growth chamber to the diphenylalanine concentration (defined as the RH-FF ratio) determines the microtubular morphology. The hexagonal arrangement of the diphenylalanine molecules first induces the hexagonal nanotubes with opposite charges on the two ends, a...