Semiconductor–Metal Transition in Magnetic Semiconductor Compounds at High Pressure

Journal of Experimental and Theoretical Physics - The magnetic, transport, and magnetotransport properties of ferromagnetic Zn0.1Cd0.9GeAs2 + 10% MnAs and Zn0.1Cd0.9GeAs2 + 15% MnAs nanocomposites...     

On the Nature of Bose-Einstein Condensation in Disordered Systems

We study the perfect Bose gas in random external potentials and show that there is generalized Bose-Einstein condensation in the random eigenstates if and only if the same occurs in the one-particle kinetic-energy eigenstates, which corresponds to the generalized condensation of the free Bose gas. Moreover, we prove that the amounts of both condensate densities are equal. Our method is based on the derivation of an explicit formula for the occupation measure in the one-body kinetic-energy eigenstates which describes the repartition of particles among these non-random states. This technique can be adapted to re-examine the properties of the perfect Bose gas in the presence of weak (scaled) non-random potentials, for which we establish similar results. In addition some of our results can be applied to models with diagonal interactions, that is, models which conserve the occupation density in each single particle eigenstate.     

On the Physical Nature of “Anomalous” High Energy Electrons in Vacuum Diodes

Russian Physics Journal - The transient process of establishing the electron current in a vacuum diode is theoretically investigated, in which the kinetic energies of electrons can exceed the...     

Conductivity of Metal–Dielectric–Semiconductor Structures Based on Ferroelectric Films

Physics of the Solid State - In this paper, we present the results of experimental studies of the frequency and temperature dependences of the electrical conductivity of...     

On the Acid–Base State of the Surface of Semiconductor Components of the ZnSe–CdS System Exposed to Different Media

Using the methods of hydrolytic adsorption, mechanochemistry, and nonaqueous conductometric titration, the acid–base properties of the surfaces of binary semiconductors and solid solutions of the ZnSe?CdS system are studied. The nature of acid sites, and the extent, character, and mechanism of the surface (absorption) interaction are established. The interrelationships in the changes of the acid–base and bulk physical properties upon changing the chemical composition are determined, which make it possible to draw conclusions that are fundamentally important in scientific and practical aspects.     

Gaseous Metal and the Problem of Vapor–Liquid (Insulator–Metal) Transition in Metal Vapors

Journal of Experimental and Theoretical Physics - We consider the main properties of a gaseous metal, viz., the state of metal vapor adjoining the vapor–fluid transition binodal. The gaseous...     

On the Geodesic Nature of Wegner’s Flow

Wegner’s method of flow equations offers a useful tool for diagonalizing a given Hamiltonian and is widely used in various branches of quantum physics. Here, generalizing this method, a condition is derived, under which the corresponding flow of a quantum state becomes geodesic in a submanifold of the projective Hilbert space, independently of specific initial conditions. This implies the geometric optimality of the present method as an algorithm of generating stationary states. The result is illustrated by analyzing some physical examples.     

Break Cohesion of Metal Contacts due to Voltage Bias

The instability of metal point contacts under voltage bias is calculated based on scattering theory. When the bias is applied, the transport channels will be closed and the chemical bonds will be broken, which modify the cohesive force of the point contact. If the cross section of the contact is narrow enough, an applied bias will break the point contact, which is in agreement with the experimental results. The effect of bias-dependent force can play an important role in the stability of a nanosize device.     

Reliability Characteristics of Diamond-Like Carbon as Gate Insulator for Metal–Insulator–Semiconductor Application

Physics of the Solid State - This study presents the reliability of diamond-like carbon (DLC) ultrathin films fabricated by DC magnetron sputtering as the gate dielectric layer in...     

The Field Effect in a Metal–Ferroelectric–Semiconductor System of Multilayer Ferroelectric Films with Various Structure Types

The ability to grow the interfacial defect-poor Sr_0.5Ba_0.5Nb₂O₆ + Ba_0.2Sr_0.8TiO₃ and Ba_0.8Sr_0.2TiO₃ + Ba_0.4Sr_0.6TiO₃ ferroelectric films onto the doped silicon substrates is discussed. A study of piezo-response via the quasi-static method (using the electrode area of 0.07 mm²) reveals that heterostructures possess an initial polarized ferroelectric state with a spontaneous polarization vector perpendicular to the substrate at any type of Si conductivity. The polarized state is established to refer to two-dimension stresses in the ferroelectric, which is tunable through a preprepared Ba_xSr_{1 – x}TiO₃ onto a sublayer substrate as well as to a thickness of this sublayer. Polarization switching in Sr_0.5Ba_0.5Nb₂O₆/Si and Ba_0.8Sr_0.2TiO₃/Si heterostructures under the external field arises at only using the barium–strontium titanate sublayer predeposited onto silicon. A 15% decrease in switching polarization in Ba_0.8Sr_0.2TiO₃/Ba_0.4Sr_0.6TiO₃/Si structures is observed after 500 h.     

On the Effect of Stochastic Fluctuations in the Dynamics of the Lifshitz–Slyozov–Wagner Model

In this paper the dynamics of a system of spherical particles that fill a small volume fraction of the space and that evolves in a concentration field is discussed. Corrections to the Lifshitz–Slyozov–Wagner (LSW) model that take into account the stochastic character of the problem are computed. It is proved, under suitable smallness assumptions for the volume fraction filled by the particles, that the effect of these corrections does not modify much the dynamics of the self-similar solutions of the LSW system of equations.     

The Stability Criterion of a Semiconductor Superlattice in the Drift–Diffusion Approximation

A criterion for the electric stability of a semiconductor superlttice placed in a longitudinal electric field has been obtained using the drift–diffusion approximation. It is demonstrated that the account for the contact ohmicity yields a stability criterion that is different from that related to the negative differential conductivity.     

Nature of the “yield tooth” under torsion in plastic-deformed whiskers

The plastic torsion of whiskers with high Peierls barriers has been studied. As the samples for the studies we chose p-type germanium whiskers with <111> growth axis. The diameter of the whisker was (5–60)·10^–6 m and the gauge length was (1–4)·10^–3 m. The whiskers were dislocation-free in the initial state. Within the framework of the continuum model developed by us for the plastic deformation of whiskers under torsion, we analyze the anomalies of the torsional stress-strain diagram under different testing conditions and with preliminary deformation. The flow tooth during the torsion of a whisker is attributable to the nonuniform distribution of dislocations over the cross section of the whisker and high barriers to the dislocation motion.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 3–8, July, 1987.     

Wave Nature of the Transverse Doppler Effect and the “Red” and “Blue” Frequency Shift Anomaly in an Electromagnetic Wave from a Moving Radiation Source

Technical Physics - The electromagnetic field of a harmonic oscillator moving at a constant velocity has been analyzed. The expression for calculating the Doppler frequency shift at relativistic...     

Anomaly in mixing properties of lithium–magnesium liquid alloy

The concentration dependent asymmetry in mixing properties of LiMg liquid alloys at 1000?K has been investigated on the basis of regular associated solution model. The analysis suggests that heterocoordination leading to the formation of chemical complex Li₂Mg is likely to exist in the melt.     

Creation and Investigation of Metal—Dielectric–Semiconductor Structures Based on Ferroelectric Films

Physics of the Solid State - The effect of the synthesis temperature on the microstructure and the electrophysical properties of metal–dielectric–semiconductor structures based on...     

Characteristics of Surface Spin Waves in a Metal–Dielectric–Ferrite–Dielectric–Metal Structure

The dispersion and isofrequency characteristics of surface spin waves in a tangentially magnetized metal–dielectric–ferrite–dielectric–metal structure are investigated. A loop-like change in the isofrequency dependences for spin waves is observed in a certain range of frequencies, and the origin of the loop is always located at wave number value k → 0.     

On the effect of lead concentration on the kinetics of contact melting in the Sn–Pb–Bi system in the presence of electromigration

It is determined by electron microscopy that the contact layer in the Sn–(Bi + 30 wt % Pb) system contains separate solid inclusions, while the contact layer in the Sn–(Bi + 40 wt % Pb) system is microheterogeneous. The observed structural states of alloys in the contact layers are explained by a change in the concentration of the initial contacting samples. The effect of the alloy structure and electromigration on the kinetics of contact melting is found.