Magnetic-Field Effects on Donor Impurity States in a Quantum Well

Green’s function technique is used to obtain the solution of Shredinger equation for impurity states in a quantum well (QW) under the magnetic field. Binding energy of impurity states is defined as poles of the wave function. We studied effects of the magnetic field magnitude and impurity position on the binding energy. The calculations were performed for both ground and excited states. The dependences of binding energies versus impurity position and magnetic field are presented for GaAs/Al0.3Ga0.7As QW.

Plasma Model of Generation and Slip of Linear Defects in Crystalline Materials

In dielectrics and semiconductors, a plasma model of the generation and slip of dislocations is considered, where under shock loads in a generalized space of rectangular pulses an alternating field forms a distribution of pairs of photoelectrons and cations;these electrons with velocities Ve create δ-collisions with cold plasma from free electrons and holes with masses me and mh (mh ≫ me), they emit and absorb longitudinal electron plasma waves whose phase velocities wpw / kpw are close to or are equal to the velocities Ve, while the frequencies wpw and wave numbers kpw of the wave packet of plasma waves are complex, the short-wave components of this wave packet at kpw ⋅ ae ≫ 1 (ae -Debye screening radius) decay in the core linear defect, and its long-wavelength components propagate in the region of the medium surrounding the core of the defect at kpw ⋅ ae <≅ 1. When a defect is generated, the distribution of cations under the influence of the internal Coulomb field shifts to the region of the first peak (protrusion) of the electron plasma wave, thereby forming a vacancy valley. When sliding under the influence of an external electric field, a cationic plasma wave consisting of a vacancy valley and two cationic protrusions moves against the background of an additional potential relief created by an electron plasma wave near the core of the defect. It has been shown that δ-collisions create flows of dynamic large-scale correlations of plasma fluctuations in the form of asymptotics of different-time correlators of density and potential fluctuations as t → +∞.

On the Relationship of the Discrete Model of the Nuclei of Linear and Planar Defects and the Continuum Models of Defects in Crystalline Materials

A physical and mathematical model of the transition from a discrete model of linear and flat defects nuclei to continuum models of defects such as dislocations and disclinations and their combinations is presented, where the tensors of energy-momentum and angular momentum of an alternating field are considered, for which the type and structure of the Maxwell stress tensor σif αβ are given and the corresponding angular momentum tensor, using the dynamic equation for the evolution of internal stresses and the correlation between the stresses σif αβ in the defect core and the elastic stresses σelik in its environment, obtains elastic displacement and deformation fields identical to these fields from Burgers and Frank vectors of continuous models. The spectral density of the autocorrelation functions of the velocity of photoelectrons Ψβ⊥(β) and cations , which transforms into linear spectra as T → 0, is considered reflecting the existence of threshold values of oscillation and rotations currents of photoelectrons and cations at all stages of plastic deformation and fracture. The features of the process of sliding linear defects in metals are disclosed.

On Separation of Charges and Formation of Linear Structures in the Nuclei of Dislocations in Metals

In metals, the non-adiabatic mechanism of charge separation into the electron, cation, and vacancy chains is considered. It includes: 1) the photoelectric effect caused by bremsstrahlung caused by the scattering of conduction electrons by impurity ions lying at the ends of these chains and oscillating with the frequency of the local phonon mode;2) knocking out from the metal cations of the matrix, sufficiently slow (in comparison with the conduction electrons) photoelectrons that pull these cations from the nodes, thereby not violating the electroneutrality condition in the model of a free electron gas as with the static state of the chains and at their motion (slipping, recrawling) in the absence of a thermal field;3) induced radiation along the line of chains;4) the formation of linear structures in the spatial lattice of octahedral interstitial sites. The conditions for the formation of quasistable bound states in the dislocation core are considered. A hypothesis is advanced that the latent energy in the dislocation cores contains a component that is of an electromagnetic nature.

Discrete Model of Plasticity and Failure of Crystalline Materials

Within the framework of a discrete model of the nuclei of linear and planar defects, the variational principles of sliding in translational and rotational plasticity, fracture by separation (cleavage) and shear (shearing) in crystalline materials are considered. The analysis of mass transfer fluxes near structural kinetic transitions of slip bands into cells, cells into fragments of deformation origin, destruction by separation and shear for fractal spaces using fractional Riemann-Liouville derivatives, local and global criteria of destruction is carried out. One of the possible schemes of the crack initiation and growth mechanism in metals is disclosed. It is shown that the discrete model of plasticity and fracture does not contradict the known dislocation models of fracture and makes it possible to abandon the kinetic concept of thermofluctuation rupture of interatomic bonds at low temperatures.

Features of Operation of Bifilar Cooper and Tesla Coils in Pulse Regime

The characteristic features of operation in a pulsed regime of bifilar Cooper and Tesla coils during magnetic pulse processing and heating of the environment are considered using the dependence of the maximum amplitude at the leading edge of the magnetic pulse on its time duration τ. The spatial distribution of the magnetic induction lines B inside and around the Cooper coil is given, where, unlike the Tesla coil, the maximum values of B arise in the extreme planes of the coil, and its central plane is zero. The defining advantages of new methods of magnetic pulse processing and heating of the environment are considered: the dependence at τ → 0;the exchange of energy between the magnetic pulse and the environment;periodic sequence of series of unipolar magnetic pulses at various processing modes. It is shown that 1) for electric fields Eout = 1010 – 1012V/m, arising at the leading edge of a magnetic pulse with duration 10-5 – 10-7 s, in the deformation fractal space the electrodynamics of these fields is nonlinear;2) inside the Tesla coil, in the package of conducting tapes and tubes, the pumping energy from the pulsed field Eout is mainly dissipated in the skin layer in the form of refractory coatings and heats the environment at all stages of plastic deformation of workpieces and heating elements up to the collapse of unstable microcracks. The coefficient of conversion of the pump energy in the pulsed regime with respect to the constant current regime is found.

Whispering Gallery Modes Formed by Scattering of an Electromagnetic Plane Wave by Two Cylinders

We report the effect of scattering of electromagnetic plane waves by two cylinders on whispering gallery mode (WGM) formation in a cylinder. WGM can occur because of the presence of additional cylinder scatterers at specific location, while WGMs can only form in a single cylinder for specific cylinder radius and/or wavelength values, the matching accuracy required would be much greater than that required in our model for the additional cylinders locations. Analysis of the general solution to the problem showed that the effect can be explained by the interference of waves scattered by additional cylinders and incident on the main cylinder.