Hyperbolic excitons in semiconductors

The energy and damping of the quasi-stationary state corresponding to a hyperbolic exciton in a semiconductor crystal are calculated. It was assumed that the screened Coulomb potential describes the interaction between the electron and hole. The resonance conditions due to the hyperbolic exciton are determined.     

Elastic dipoles in the model of single-crystal and amorphous copper

The characteristic values of the elastic polarizability tensor components of point defects in crystalline and amorphous copper, which determine changes in the elasticity tensor components upon introduction of defects, have been found using the molecular dynamics method. A relation of the elastic polarizability tensor with the main parameter of the interstitialcy theory, i.e., shear susceptibility, has been established. An analysis of the elastic polarizability tensors of defects in crystalline and amorphous copper has demonstrated that, in a noncrystalline structure, there are specific atomic configurations that under deformation manifest themselves similarly to elastic dipoles (interstitial atoms in a dumbbell configuration) in single-crystal copper.     

Elastic Dipoles in Crystal and Glassy Aluminum and High-Entropy Fe20Ni20Cr20Co20Cu20 Alloy

JETP Letters - Molecular dynamics simulation has shown that anisotropic local atomic configurations, which are in essence elastic dipoles, exist in noncrystalline structures of Al and FeNiCrCoCu....     

Relation between the Shear and Dilatational Elastic Energies of Interstitial Defects in Metallic Crystals

JETP Letters - Molecular statics simulation of interstitial defects for four metals with a face-centered cubic lattice has been carried out. The volumes of Voronoi polyhedra are calculated for...     

Point Defects and Their Properties in the Fe20Ni20Cr20Co20Cu20 High-Entropy Alloy

JETP Letters - The characteristics of interstitial atoms and vacancies in the Fe20Ni20Cr20Co20Cu20 high-entropy alloy have been determined by the molecular dynamics and statics methods. The effect...     

Premelting generation of interstitial defects in polycrystalline indium

High-precision measurements of the shear modulus of polycrystalline indium from room temperature to the melting temperature T _m and molecular statics computer simulation have been performed. It has been found that interstitial defects are intensely generated near T _m in a dumbbell (split) configuration and their concentration can exceed the concentration of vacancies.     

Catalytic Halocarbon Decomposition in a Microwave Post-discharge

Plasma Chemistry and Plasma Processing - A computer simulation of chemical, charged-particle, and excited-particle kinetics in a microwave post-discharge in humid air with halocarbon (CCl3F) traces...     

Effect of vacancies and interstitials in the dumbbell configuration on the shear modulus and vibrational density of states of copper

It has been shown by the molecular dynamics method that the introduction of interstitials in the dumbbell configuration into the copper crystal leads to a significantly stronger shear modulus reduction than the vacancy introduction. Specific low-frequency modes appear in the spectrum of vibrational states of “defect” atoms. The vacancy formation enthalpy weakly depends on their concentration, and the interstitial dumbbell formation enthalpy at high concentrations can decrease by a factor of 8. In this case, the radial distribution function takes the form characteristic of noncrystalline materials. The results obtained confirm the interstitial theory of the condensed state.     

Contribution of interstitial defects and anharmonicity to the premelting increase in the heat capacity of single-crystal aluminum

With the use of experimental data on the temperature dependence of the concentration of interstitial atoms, it has been shown within the interstitial theory that the premelting nonlinear increase in the heat capacity of aluminum can be caused by the intense generation of interstitial defects in a dumbbell configuration.     

Kinetic processes of muonium formation by thermalized electrons in the spur model

Diffusion of a thermalized electron in the field of a Coulomb centre is considered. The time dependence of the probability for the electron not to be captured by the Coulomb centre ( ⁺) at the momentt,P _D (t), is obtained. The quantityP _D (t) coincides with the precession amplitude at the muon frequency and is determined by the parameter/l _CT ( is an averaged distance from an electron to a muon att=0 andl _CT =e ²/(2T) is the Onsager length) that reflects the relation between electron potential and kinetic energies at t=0. When/l _CT –1 the precession amplitudeP _D (t) decreases up to 30% during the timel _CT ² /D-(D-is the diffusion coefficient) and then it becomes almost constant. The dependence ofP _D () on/l _CT is presented.