Growth of SiC films by the method of substitution of atoms on porous Si (100) and (111) substrates

The mechanisms of growth of silicon carbide (SiC) films by the method of substitution of atoms on macro- and mesoporous silicon substrates (Si) of p- and n-type conduction are investigated. Significant dependence of the rate and the mechanism of nucleation of SiC layers on Si on the type of Si doping and its crystallographic orientation is experimentally found. Comparison of the experimental data with the theoretical results obtained earlier is performed. It is shown that the presence of the system of pores on the surface allows one to significantly increase the thickness of silicon transformed into SiC during the process of synthesis by the method of substitution of atoms, which was equal to 115 microns in our experiments. The obtained samples are studied by methods of scanning electron microscopy, micro-Raman spectroscopy, and X-ray diffraction analysis. Numerical simulation of the distribution of elastic stresses caused by the difference in thermal expansion coefficients (TEC) in the heterostructures of GaN/SiC/porous Si/Si is conducted. It is revealed that the presence of pores in the near-surface layers of Si leads to considerable relaxation of elastic stresses in GaN films caused by differences in the TEC between GaN and Si

Spin 1 Particle with Anomalous Magnetic Moment in an External Uniform Electric Field

Within the matrix 10-dimensional Duffin–Kemmer–Petiau formalism applied to the Shamaly–Capri field, we study the behavior of a vector particle with anomalous magnetic moment in the presence of an external uniform electric field. Separation of variables in the wave equation is performed using projective operator techniques and the theory of DKP-algebras. The whole wave function is decomposed into the sum of three components Ψ0, Ψ+, Ψ-. It is enough to solve an equation for the main component Φ0, two remaining ones are determined by it uniquely, The problem is reduced to a system of three independent differential equations for three functions, which are of the type of one-dimensional Klein–Fock–Gordon equation in the presence of a uniform electric field modified by the anomalous magnetic moment of the particle. Solutions are constructed in term of confluent hypergeometric functions. For assigning physical sense for the solutions, one should impose special restriction on a parameter related to the anomalous moment of the particle. The neutral spin 1 particle is considered as well. In this case, the main manifestation of the anomalous magnetic moment consists in modification of the ordinary plane wave solution along the electric field direction. Again one have to impose special restriction on the parameter related to the anomalous moment of the particle

Spin 1/2 particle with two masses in magnetic field

In the present paper, the generalized equation for spin 1/2 particle with two mass states is investigated in presence of an external uniform magnetic field. After the separation of variables in cylindric coordinates, the problem reduces to a system of 8 first order differential equations, from where follows the system of related four second order differential equations. After the diagonalization of the mixing term, the separate equations for four functions are derived, in which the spectral parameters coincide with the roots of the 4-th order polynomial. The solutions are constructed in terms of confluent hypergeometric functions, and the analytical formulas for the two series of energy spectrum are found in explicit form as solutions of 4-th order algebraic equations; however these prove to be cumbersome and useless for our purposes. The numerical study of the energy levels is performed depending the parameter γ, determining the mass values, on the magnitude of magnetic field and magnetic and main quantum numbers: E = E1,2(γ, B; m, n). In particular, it is shown that the physical energy spectrum for a two mass fermion differs significantly from the energy spectrum of an ordinary Dirac particle

Spin 1 particle with anomalous magnetic moment in the external uniform electric field

В рамках 10-мерного матричного формализма Даффина-Кеммера-Петье, примененного в исследовании векторного поля Шамали-Капри, исследуется поведение частицы со спином 1 и аномальным магнитным моментов во внешнем однородном электрическом поле. Разделение переменных в волновом уравнении выполнено с использованием техники проективных операторов и алгебраических свойств матриц Даффина-Кеммера-Петье

Сферические решения уравнения для частицы со спином 3/2

The wave equation for a spin 3/2 particle, described by 16-component vector-bispinor, is investigated in spherical coordinates. In the frame of the Pauli – Fierz approach, the complete equation is split into the main equation and two additional constraints, algebraic and differential

Electrodynamics, complex rotation group, media

The matrix form of the Maxwell theory in the form of Riemann – Silberstein – Majorana – Oppenheimerand, based on the theory of complex rotation group, may be effectively used in practical calculation when studying electromagnetic problems. This representation is closely related to spinor formalism in Maxwell theory

Fermion with Three Mass Parameters, P-Asymmetric Interaction with External Fields

The theory of a P-asymmetric spin 1/2 fermion with three mass parameters is developed. It is based on 20-component representation of the Lorentz group. Starting with the Gel’fand - Yaglom approach, we derive a spin-tensor form of a generalized wave equation. In absence of external electromagnetic fields, the system of equation can be transformed to the form of three separate P-asymmetric Dirac-like equations for bispinor wave functions with different masses. The values of masses values vary within some freedom, determined by parameters of the model

How Does Thermal Poling Produce Interstitial Molecular Oxygen in Silicate Glasses?

Thermal poling of glasses induces structural and compositional modification and breaks central symmetry of these initially isotropic media. In spite of numerous experimental data accumulated, little is known about the processes occurring in soft glasses under this processing. We use micro-Raman technique to study the formation of interstitial molecular oxygen and structural modification of the subsurface layer of a soda-lime silicate glass in the course of thermal poling. The presence of O₂ is demonstrated in cation-depleted subanodic region of the glass, the thickness of which depends on the charge passed during the poling procedure and, in our experiments, reaches one micron. O₂ concentration in this layer is independent of the charge passed and is on the order of 3 × 10²⁰ cm^–3 being maximal in anodic surface craters arising because of poling current nonuniformities. O₂ generation is accompanied by an increase in the concentration of three-membered Si–O rings in the modified region of the glass matrix. The ways of nonbridging oxygen recombination are discussed and proposed as the main mechanism of the interstitial O₂ formation