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.     

Bound States in the Continuum in Magnetophotonic Metasurfaces

JETP Letters - We analyze the enhancement mechanisms of magneto-optical effects in all-dielectric metasurfaces caused by the bound state in the continuum resonance. In a structure under study, a...     

Hybrid impurity resonance in a three-dimensional Anisotropic quantum wire

The absorption of electromagnetic radiation of a three-dimensional quantum wire is theoretically investigated taking into account the processes associated with simultaneous scattering from ionized impurities. The absorption coefficient is studied as a function of the radiation frequency and the magnetic field strength. The shape of the absorption curve is analyzed.     

Magnetic response of an electron gas in a quantum ring of non-zero width

An investigation of the magnetic moment of an electron gas in a quantum ring of non-zero width is made. Analytic expressions are obtained for the magnetic moment. For the magnetic moment of the system, the dependence on temperature and parameters of the ring are found and investigated in detail. De Haas–van Alphen and Aharonov–Bohm oscillations are investigated.     

Parametric Amplification of High-Frequency Radiation by Point Josephson Junctions Near Shapiro Subharmonic Steps

Physics of the Solid State - Parametric amplification of a high-frequency radiation by point-like Josephson junctions in the cavity has been studied within a resistive model. It is shown...     

Dynamic pressing of titanium for producing an ultrafine-grained structure

Dynamic equal-channel angular pressing, a new method for the intense plastic deformation of materials, was developed and applied to titanium, as an example. A sample, accelerated in a gun to a velocity of 300 m/s, impinged on a matrix with intesecting channels. The deformation of titanium occurred at a shear-deformation rate of 10⁴–10⁵ s^?1 and pressure of several GPa. Upon deformation, the strength of titanium increased by a factor of 2, with the plasticity remaining at an acceptable level. Metallographic and electron microscopy analyses demonstrated that, under the action of intense deformation, the initial course-grained structure of titanium transforms into an ultrafine-grained one.     

High tetraalkylaluminate fluxionality in half-sandwich complexes of the trivalent rare-earth metals

Steric factors govern the formation of half-sandwich complexes (C5Me4R)Ln[N(SiHMe2)2]2 according to acid-base reactions utilising Ln[N(SiHMe2)2)3(thf)2 and substituted cyclopentadienes. Subsequent trimethylaluminium-promoted silylamide elimination produces the first half-sandwich bis(tetramethylaluminate) complexes (C5Me4R)Ln(AlMe4)2.     

Topological Analysis of Electron Densities: Is the Presence of an Atomic Interaction Line in an Equilibrium Geometry a Sufficient Condition for the Existence of a Chemical Bond?

The structure, energetics, and electron density in the inclusion complex of He in adamantane, C10H16, have been studied by density functional theory calculations at the B3LYP6-311++G(2p,2d) level. Topological analysis of the electron density shows that the He atom is connected to the four tertiary tC atoms in the cage by atomic interaction lines with (3,-1) critical points. The calculated dissociation energy of the complex He@adamantane(g)=adamantane(g) + He(g) of DeltaE=-645 kJ mol(-1) nevertheless shows that the He-tC interactions are antibonding.     

Generalization of the Kerr-Newman solution

An exact four-parameter solution of the Einstein-Maxwell equations is derived. This solution constitutes a generalization of the Kerr-Newman metric. It incorporates a quadrupole deformation of a rotating charged mass.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 119–120, November, 1991.     

Topological Photonics (Brief Review)

JETP Letters - Topological insulators, originally discovered in the context of condensed matter physics, have provided a powerful source of inspiration for the design of novel types of photonic...