In simple ionic crystals, intrinsic point defects must satisfy electrical neutrality and exist as Schottky defects. magnesium oxide (MgO), a defect is then combination of anionic cationic vacancies. Since vacancies are charged, the stable configuration corresponds to bound pair opposite signs. this study, we investigate kinetics formation migration such on long timescales reaching in some cases...

We study the diffusion processes of a real scalar field in presence distortion induced by chiral topological defect. The defect modifies usual Euclidean background geometry into non-diagonal Riemann–Cartan characterized singular torsion field. new form equation is established and distribution vicinity investigated numerically. Results show high sensitivity to boundary conditions. In transient r...

Using a linear optical diffraction technique, we have systematically investigated the defect effects on quantum surface diffusion of hydrogen on Pt(111) surfaces. The quantum tunneling effect was clearly observed for hydrogen diffusion at low temperatures as manifested by a leveling off of the diffusion coefficient on flat surfaces. The strong influence of surface defects on the quantum diffusi...

An identical set of thermal oxidation and nitridation experiments has been performed for four common dopants and self-diffusion in Si. Selectively perturbing the equilibrium point-defect concentrations by these surface reactions is a powerful tool for identifying the relative importance of the various atomic-scale diffusion mechanisms. We obtain bounds on the fractional contributions of the sel...

A unified physically based ion implantation damage model has been developed which successfully predicts both the impurity profiles and the damage profiles for a wide range of implant conditions for arsenic, phosphorus, BF2, and boron implants into single-crystal silicon. In addition, the amorphous layer thicknesses predicted by this new damage model are also in excellent agreement with experime...

A new approach to the derivation of local extremum diminishing finite element schemes is presented. The monotonicity of the Galerkin discretization is enforced by adding discrete diffusion so as to eliminate all negative off-diagonal matrix entries. The resulting low-order operator of upwind type acts as a preconditioner within an outer defect correction loop. A generalization of TVD concepts i...

this is a case presentation of a 26-year-old woman with a moderate-sized atrial septal secundum defect (17mm) who underwent catheterism, during which an amplatzer septal occluder number 26 was inserted successfully. on the second postoperative day, she deteriorated and a clinical examination showed a typical tamponade. after a percutaneous aspiration of the pericardial cavity and transient impr...

Theoretical studies of point defect interactions and structural stability of compounds have been performed using density functional theory. The defect-related properties, such as activation energy of diffusion, electronic and magnetic structure of selected materials have been studied. The major part of the present work is devoted to a very important material for semiconductor industry, GaAs. Th...

Spatiotemporal chaos, or disorder in space and chaos in time, is studied in direct numerical simulations of Rayleigh-Bénard convection. In particular, the following results pertaining to spiral defect chaos are discussed. First, in the absence of the mean flow, spiral defect chaos is found to collapse to a stationary pattern comprising textures of stripes with angular bends. The quenched patter...

Since many years, the contribution of vacancies (V ) and self-interstitials (I ) to silicon (Si) self-diffusion is a matter of debate. Native defects and their interaction among themselves and with foreign atoms influence the processes taking place during device fabrication, starting with the growth of Si single crystals and ending with doping of nanosized electronic devices. Considering this r...