Electron–electron scattering and the transport properties of two-dimensional ballistic contacts

Recent results on the effect of electron–electron collisions on the electric properties of contacts to a twodimensional electron gas with a direct conductivity in the absence of scattering by impurities and boundaries have been reviewed. A correction to the conductance of such contacts owing to the electron–electron scattering can be either positive or negative depending on the contact geometry. The magnitude of this correction strongly depends on the magnetic field.     

Electron Momentum Spectroscopy of the Frontier Orbitals of Chlorodifluoromethane

We report on the first measurement of the electron momentum distributions of the three outermost valence orbitals for chorodifluoromethane(CHF2Cl)by binary(e,2e) electron momentum spectroscopy.The experimental data are compared with Hartree-Fock and density functional theory(DFT) calculations employing 6-31G,6-311 G^** and AUG-cc-pVQZ basis sets.For the summed momentum distribution of 8α′ 5α″ 7α′ orbitals,the DFT/.AUG-cc-pVQZ calculation gives the best fit.A very large and diffuse basis set,AUG-cc-pVQZ,is employed in the calculations to approach the Hartree-Fock limit of the basis set,but the improvement of the calculation quality is little in comparison with that calculated with the 6-311 G^** basis set,This indicates that the 6-311 G^** basis set is nearly saturated for the calculations of these three orbitals of CHF2Cl,and it is unnecessary to employ a larger basis set in the calculations.     

Current Filamentation and Resonant Transport of the Relativistic Electron Beam in Dense Plasmas

The transport of a relativistic electron beam in dense plasmas with a cold return electron current is examined by two-dimensional particle-in-cell simulation.The filamentation and coalescence of currents and related magnetic field patterns,caused by the electromagnetic-benm-plasma instability,are observed.In the later simulation time,the electrons of the relativistic electron beam are trapped into the potential wells of the wave excited by the instability,and transport resonantly with the wave.     

Measurement of Specimen Thickness by Using Electron Holography and Electron Dynamic Calculation with a Transmission Electron Microscope

A method of transmission-electron microscopy for accurate measurement of specimen thickness has been proposed based on off-axis electron holography along with the dynamic electron diffraction simulation.The phase shift of the exit object wave with respect to the reference wave in vacuum,resulting from the scattering within the specimen,has been simulated versus the specimen thickness by the dynamic electron diffraction formula.Offaxis electron holography in a field emission gun transmission-electron microscope has been used to determine the phase shift of the exit wave.The specimen thickness can be obtained by match of the experimental and simulated phase shift.Based on the measured phase shift of the [110] oriented copper foil,the thickness can be determined at a good level of accuracy with an error less than-10%.     

Electron Single and Double-slit Diffraction in the Temporal Domain

Few-cycle pulses with stable and controllable relative phase between the carrier wave and the envelope （CE phase） have become available as research tools. The actual shape of the electric field of such a pulse strongly depends on this phase, and so do the physical processes the pulse generates. Owing to its pronounced nonlinearity, above-threshold ionization （ATI） provides an excellent example. In particular, the rescattering-induced high- energy part of the ATI spectrum exhibits a dramatic dependence on the value of the CE phase. Moreover, the backward/forward symmetry of the ATI spectrum generated by a, long pulse is broken by a few-cycle pulse. Therefore, analyzing the spectrum in two opposite directions provides a very accurate means of measuring the CE phase.     

Interactions between Surface Impurities and the Electron–Hole System of a Semiconductor Crystal

The effects of creation and annihilation of impurities on the surface of a highly doped semiconductor under changes in the surface concentration n of dopant atoms constituting impurities are predicted theoretically. The effects are determined by electrostatic interactions of charged surface impurity species with charge carriers and semiconductor ions. The effects are observed in a certain range of n, provided the surface impurities exhibit donor (acceptor) properties, and the semiconductor is doped with an acceptor (donor) impurity.     

On the Scattering of the Electron off the Hydrogen Atom and the Helium Ion Below and Above the Ionization Threshold: Temkin–Poet Model

We generalize here the splitting approach to the long range (Coulomb) interaction for the three body scattering problem. With this approach, the exterior complex rotation technique can be applied for systems with asymptotic Coulomb interaction. We illustrate the method with calculations of the electron scattering on the hydrogen atom and positive helium ion in the frame of the Temkin–Poet model.     

Electron spin resonance and structure of the ionic radical, ·PO3 =

It is shown that the ionic radical, ·PO₃ ⁼, is formed by the action of γ-rays on disodium ortho-phosphite pentahydrate. The hyperfine coupling to the ³¹P nucleus has principal values of 1967, 1514 and 1513 Mc/s and is consistent with a pyramidal ion having OPO angles of 110°.     

Electron scattering with the excitation of the 15.11 MeV state of12C and theπ 12B12C coupling constant

Theπ ¹²B¹²C coupling constant is extracted from the data on theM1 form factor of¹²C using the PCAC and CVC hypotheses. The extrapolation of the form factor to the pion pole using analyticity arguments leads to the value \(f_{\pi ^{12} B^{12} C}^2 = 0.052\) . Our present knowledge of this coupling constant is discussed.     

Electron Correlation in the Final Continuum of Ionization Hydrogen by 150-eV Electron Impact

Electron correlation in triple differential cross sections for ionization of atomic hydrogen by electron impact is analysed for the case of coplanar asymmetric geometry within the framework of the two-potential formulae. Based on the approximations of projectile and faster-electron plane wave, the transition matrix element is analytically expressed to be a product of two factors: the correlation factor of two electrons in the final channel and the structure-scattering factor. The contribution of both the factors to the angular distribution of the triple differential cross section is calculated. The present results are compared with the experimental data and the other theoretical calculations for the incident energy of 150eV.     

Charge Conservation,Klein’s Paradox and the Concept of Paulions in the Dirac Electron Theory

An algebraic block-diagonalization of the Dirac Hamiltonian in a time-independent external field reveals a charge-index conservation law which forbids the physical phenomena of the Klein paradox type and guarantees a single-particle nature of the Dirac equation in strong external fields. Simultaneously, the method defines simpler quantum-mechanical objects—paulions and antipaulions, whose 2-component wave functions determine the Dirac electron states through exact operator relations. Based on algebraic symmetry, the presented theory leads to a new understanding of the Dirac equation physics, including new insight into the Dirac measurements and a consistent scheme of relativistic quantum mechanics of electron in the paulion representation. Along with analysis of the mathematical anatomy of the Klein paradox falsity, a complete set of paradox-free eigenfunctions for the Klein problem is obtained and investigated via stationary solutions of the Pauli-like equations with respective paulion Hamiltonians. It is shown that the physically correct Dirac states in the Klein zone are characterized by the total particle reflection from the potential step and satisfy the fundamental charge-index conservation law.     

Effects of the Electron—Electron Interaction in the Magneto-Absorption Spectra of HgTe/CdHgTe Quantum Wells with an Inverted Band Structure

JETP Letters - Magneto-absorption in HgTe/CdHgTe quantum wells with an inverted band structure in magnetic fields up to 30 T has been studied. It has been shown that the positions of...     

A Monte Carlo Study of Low-Energy Electron Transport in Liquid Water： Influence of the Rutherford Formula and the Mott Model

Influence of the Rutherford formula and the Mott model on the Monte Carlo simulation of low-energy electron （〈10 keV） transport in liquid water is investigated. One of the features of the constructed Monte Carlo code is the implementation of the new optical-data model from Emfietzoglou et al. in inelastic cross section based on the dielectric response theory. In addition, a novel mean elastic cross section by means of the Mott model is proposed to calculate the electron elastic scattering for high simulation efficiency. The systematical calculations of both the distribution of energy depositions and penetration parameter for low-energy electrons in liquid water are performed by using the Rutherford formula and the Mott model, respectively, for the elastic collisions in the simulations. The calculated results show that the effect of the two models is evident at energies below about 1 keV.     

Primary Results of ECRH Experiment and Electron Heat Transport on the HL-2A Tokamak

As an ordinary mainly auxiliary heating on tokamak plasma, electron cyclotron resonance heating （ ECRH ） is an useful method to the study of electron heat transport and confinement performance. In this work, primary results of ECRH experiments on the HL-2A tokamak are presented. The features of confinement and electron heat transport during ECRH are analyzed.     

Electron States of Few—Electron Quantum dots

We study few-electron semiconductor quantum dots using the unrestricted Hartree-Fock-Roothaan method hased on the Gaussian basis.Our emphasis is on the energy level calculation for quantum dots.The confinement potential in a quantum dot is assumed to be in a form of three-dimensional spherical finite potential well.Some valuable results,such as the rearrangement of the energy level,have been obtained.     

Klein–Nishina Effect and the Cosmic Ray Electron Spectrum

Radiative energy losses are very important in regulating the cosmic ray electron and/or positron(CRE) spectrum during their propagation in the Milky Way. Particularly, the Klein–Nishina(KN) effect of the inverse Compton scattering(ICS) results in less efficient energy losses of high-energy electrons, which is expected to leave imprints on the propagated electron spectrum. It has been proposed that the hardening of CRE spectra around 50 GeV observed by Fermi-LAT, AMS-02, and DAMPE could be due to the KN effect. We show in this work that the transition from the Thomson regime to the KN regime of the ICS is actually quite smooth compared with the approximate treatment adopted in some previous works. As a result, the observed spectral hardening of CREs cannot be explained by the KN effect. It means that an additional hardening of the primary electrons spectrum is needed. We also provide a parameterized form for the accurate calculation of the ICS energy-loss rate in a wide energy range.     

Double Electron–Electron Resonance Between Trapped Electron and Hole in a Semiconductor

We demonstrate the spin interactions between dispersedly trapped electrons and holes in a semiconductor using the double electron–electron resonance (DEER) method of the pulsed electron paramagnetic resonance (EPR) techniques. An aluminum-doped titanium dioxide crystal is adopted as a spin system, in which optically generated electrons and holes are trapped, to reveal EPR signals that appear close to each other at a selected crystal orientation under an external magnetic field. We used the four-pulse DEER method by applying two microwave frequencies to a microwave cavity for pumping electrons and probing holes at the optimum temperature of 32 K. The dipolar modulation in the probed signal by pumping interacting spins was successfully detected. The observed non-oscillating decay shape indicates that the detected interaction is caused by widely distributed trapped electron and hole spins over long distances. We were able to extract a spin-pair distribution function by the first derivative of a background-corrected curve, referring to a previously reported method.     

Energy Quantization and Probability Density of Electron in Intense-Field-Atom Interactions

We find that, due to the quantum correlation between the electron and the field, the electronic energy becomes quantized also, manifesting the particle aspect of light in the electron-light interaction. The probability amplitude of finding electron with a given energy is given by a generalized Bessel function, which can be represented as a coherent superposition of contributions from a few electronic quantum trajectories. This concept is illustrated by comparing the spectral density of the electron with the laser assisted recombination spectrum.