Electron and Phonon in Neutron Scattering of Semiconductor Crystals

An interaction of electron with harmonic, localized and anharmonic fields has been taken to develop the theory of neutron scattering. The Fourier transformed electron Green’s function is evaluated by Zubarev equation of motion technique of quantum dynamics and Dyson equation approach. The expression of Debye-Waller factor (DWF) has been obtained from electron phonon linewidth. The study of its (DWF) effect on differential scattering cross-section through temperature, electron phonon coupling constant and excitations has been investigated in this approach.     

General Solutions of Geometric Phase of Neutron in Rotating Magnetic Fields

The exact solutions of the closed evolution of spin states in rotating magnetic fields are described for the most general cases via eigenstate method. A simple algorithm for calculating the geometric phase is exploited.     

Formation of Annihilation-Cyclotron Lines in Strong Magnetic Fields Near Neutron Stars

We study cyclotron and polarization spectral features in magnetized vacuum at frequencies near the one-photon annihilation resonance in a subcritical magnetic field. On the basis of this study, we propose a new method for determination of the neutron-star magnetic field. Using the dipole-field model, we show that detection of the annihilation line in absorption and an additional line in emission at MeV energies is evidence of the existence of a magnetic field (2.8-3.6)· 10¹²G on the surface of a neutron star.     

均匀强磁场中中子星物质的物态方程

在Walecka模型的平均场近似下,研究了由质子、中子和电子组成的中子星物质在均匀强磁场中的性质,发现磁场增强,物态方程会在一定程度上变硬,中子所占比例显著增加,质子和电子所占比例会显著减少,磁场对物态方程的影响比它对粒子组分的影响小.本文还分别利用流体力学公式和热力学公式分别计算了中子星物质的压强,发现磁场越强,用这两种方式计算的压强越接近,当磁场为10¹⁴T时,它们完全重合.     

Effect of Weak Magnetic Fields on the Electric Properties of CdTe Crystals

The effect of static and pulsed magnetic fields (~1 T) on the electrical conductivity of CdTe crystals has been revealed. With a delay after the magnetic exposure of crystals, the effect is observed in the form of two peaks of their conductivity with the subsequent relaxation return. The first peak at both types of magnetic treatment is observed ~1 h after exposure and its amplitude exceeds the background value by ~23–36% (the larger value corresponds to the static field). The second peak appears in both cases also at commensurate but much larger delays of ~50–60 h, and its amplitudes are much different for the two types of exposure, exceeding the background by ~60% for the static field and only by ~11% for the pulsed field. Possible mechanisms of the observed effects have been discussed.     

The Equation of State of Neutron Star Matter in Uniform Strong Magnetic Fields

The Walecka model is extended to the neutron star matter, and in it's mean field approximation, the properties of neutron star matter consisted of proton, neutron and electron in uniform strong magnetic fields are studied. it is found that the ~equation of state (eos) becomes stiffer in some degree, and the ratio of neutron increase evidently while the one of proton and electron decrease with the magnetic field being stronger. the influence of the magnetic to the eos is smaller than the one to the fractions of the particles. the pressure of the neutron star matter is calculated by hydrodynamics and thermodynamics respectively. the stronger the magnetic field is, the more adjacent the curves of pressure depicted in these two ways are, and they are in superposition completely when the magnetic field is 10¹⁴T.     

Influence of Electric and Magnetic Fields on Interband Luminescence in Semiconductor Quantum Wires

Optics and Spectroscopy - Interband optical transitions in quantum wires have been theoretically investigated in the model of parabolic potential in electric and magnetic fields directed...     

Electronic structure of ZnS:Co and ZnSe:Co crystals

The x-ray photoelectron spectra of the valence bands and inner Co 2p levels of solid solutions of the wide-gap semiconductors ZnS, ZnS:Co, ZnSe, and ZnSe:Co are investigated. The x-ray photoelectron Co 2p spectrum of the ZnS:Co crystal indicates a 3d configuration of the ground state of cobalt and strong covalence of the cobalt-sulfur bond, but somewhat weaker than for CoS. It is established that the edge of the valence band recedes by 0.7±0.1 eV in transition from ZnSe to ZnS. Fiz. Tverd. Tela (St. Petersburg) 39, 1971–1974 (November 1997)     

Effect of Superstrong Magnetic Fields on Nuclear Energy Generation Rate in the Crust of Neutron Stars

This paper shows that superstrong magnetic fields （such as those of magnetars） can increase the energy generation rate many times in the crust of neutron stars. This result undoubtedly not only influences the cooling of neutron stars and the X-ray luminosity observed of neutron stars but also the evolution of neutron stars.     

Simulation of nonlinear optical absorption in ZnSe:Co crystals

The paper presents theoretical approach to simulation of nonlinear optical absorption in zinc selenide crystals doped with cobalt (II) ions (ZnSe:Co²⁺), which was reported by us earlier (Opt. Laser Technology, V. 35, (2003), 169). We used ZnSe:Co²⁺ crystals as saturable absorbers for generation of giant-pulse eye-safe laser radiation. It was found that minimal optical losses (maximal final transmission) occurred for ZnSe samples containing 1.6×10¹⁹ cm⁻³ of Co²⁺ ions. Band structure and photoinduced molecular dynamics simulations were performed to explain the parabolic dependence of optical losses versus Co²⁺ concentration. The minimum was shown to be the result of photoinduced anharmonic electron–phonon interaction.     

A Single-Crystal Neutron Diffraction Study on Magnetic Structure of the Quasi-One-Dimensional Antiferromagnet SrCo_2V_2O_8

The magnetic structure of the spin-chain antiferromagnet SrCo_2 V_2 O_8 is determined by single-crystal neutron diffraction experiment.The system undergoes a long-range magnetic order below the critical temperature T_N=4.96 K.The moment of 2.16μ_B per Co at 1.6 K in the screw chain running along the c axis alternates in the c axis.The moments of neighboring screw chains are arranged antiferromagnetically along one in-plane axis and ferromagnetically along the other in-plane axis.This magnetic configuration breaks the four-fold symmetry of the tetragonal crystal structure and leads to two equally populated magnetic twins with the antiferromagnetic vector in the a or b axis.The very similar magnetic state to the isostructural BaCo_2V_2O_8 warrants SrCo_2V_2O_8as another interesting half-integer spin-chain antiferromagnet for investigation on quantum antiferromagnetism.     

Dosimetry Methods of Fast Neutron Using the Semiconductor Diodes

Semiconductor detectors based on a silicon pin diode are frequently used in the detection of different nuclear radiations. For the detection and dosimetry of fast neutrons, these silicon detectors are coupled with a fast neutron converter. Incident neutrons interact with the converter and produce charged particles that can deposit their energy in the detectors and produce a signal. In this study, three methods are introduced for fast neutron dosimetry by using the silicon detectors, which are： recoil proton spectroscopy, similarity of detector response function with conversion function, and a discriminator layer. Monte Carlo simulation is used to calculate the response of dosimetry systems based on these methods. In the different doses of an 241Am-Be neutron source, dosimetry responses are evaluated. The error values of measured data for dosimetry by these methods are in the range of 15-25%. We find fairly good agreement in the 241Am-Be neutron sources.     

Magnetic Fields in the Early Universe

We discuss magnetic fields in the early universe— their origin, their possible detection, andlimits and values today and at early times.     

Characterization of the edge emission in Na doped ZnSe

Analysis of edge emission spectra of Na-diffused ZnSe is compared with theoretical predictions of donor-acceptor transition behavior. It is found that the R₀ series fits the criteria for D—A transitions. Mass analysis of the samples studied tends to confirm Na as the responsible acceptor. Properties of R₀ and the I^Y₁ excitonic line are discussed.     

Localization of Excitons on Planar Defects in Semiconductor Crystals

JETP Letters - Motivated by recent experimental and computational investigations of bilayer, hydrogenated and fluorinated graphene, we apply the formalisms of U(1) quantum electrodynamics and SU(2)...     

Diffraction Fields in the Focal Space of Symmetrical Hyperbolic Focusing Lens

The fields refracted by circular symmetric hyperbolic lens illuminated by a linearly polarized plane wave are calculated from the induced surface currents. It is shown that the fields in the axial region approximate to the fields in the aperture of corrugated horn under balanced hybrid condition. The image structures for different focal ratio are compared with the classical Airy pattern, deduced by scalar analysis, of optical focusing systems. The coupling between the lens and a corrugated horn at different position on focal plane are presented. The lens resolution and pix numbers are evaluated.     

Peculiarities of Laue Diffraction of Neutrons in Strongly Absorbing Crystals

Journal of Experimental and Theoretical Physics - Well-known Kato’s theory of the Laue diffraction of spherical X-ray waves is generalized to the case of the neutron diffraction in strongly...     

Letter: Behavior of Magnetic Tubes in Neutron Star's Interior

It is found from Maxwell's equations that the magnetic field lines are good analogues of relativistic strings. It is shown that the superconducting current in the neutron star's interior causes local rotation of magnetic flux tubes carrying quantized flux.