Anomalous properties of 2-D electrons in a magnetic field

In strong magnetic field and at low temperature, 2-D electron systems are expected to show distinctive temperature oscillations when the field is changed adiabatically.     

On existence of quantum diffusion of 2-D electrons at the surface

A quantum diffusion of 2-D electrons at a metal substrate has been shown to arise because of surface-bulk interaction via hybridization provided that the surface Fermi momentum has been smaller than the bulk one. The diffusion coefficient D has been found to depend nonmonotonously on sample dimensions L. An initial decrease in D has turned into an increase for sufficiently large L. The minimum in D has nonanalytically depended on the hybridization constant: $\text{D}{}_{\mathrm{<mtext>min</mtext>}}\text{～g}{}^{\mathrm{<mtext>4</mtext><mtext>3</mtext>}}$. The effects predicted have resulted from the instability of the zero-component nonlinear σ-model with respect to inclusion of certain symmetry — breaking terms which have proved to increase under RG transformations.     

Correlation effects on the energy spectra of quantum dot electrons with harmonic model interactions

The low lying excitation energy spectra of two, three and five quantum dot electrons with harmonic model interactions in a large magnetic field are calculated by the Hartree Fock(HF) methods. Correlation effects on the energy level structures are investigated by comparing the HF results with the exact ones. It is found that the pure collective excitations(center of mass mode quanta) existing in the exact energy spectra do not appear in the HF energy spectra. The degeneracies of energy levels are also re...     

Binding energy of silicon 2p electrons in iron silicides

Experimental data for the binding energies of Si 2p electrons in a number of stable and metastable iron silicides are analyzed and generalized. The silicides are applied on the Si(100)2 × 1 and Si(111)7 × 7 reconstructed single-crystal faces with solid-phase epitaxy. Core electron spectra are taken by means of high-energy-resolution photoelectron spectroscopy using synchrotron radiation. It is shown that the binding energies of Si 2p electrons in stable silicides, as well as in the silicon-iron solid solution, increase with increasing silicon content in them, since the role of interatomic relaxation in photoelectron excitation events grows feeble.     

Magnetic exchange energy of two-dimensional electrons

The exchange energy of a two-dimensional electron gas was evaluated exactly in the presence of a magnetic field when only the lowest Landau level is occupied fractionally.     

The measured energy loss of high energy electrons in aluminum

The energy distributions of electrons of about 54, 75 and 97 Mev have been measured before and after passing through aluminum absorbers of thicknesses ranging from 0.730 to 5.574 gm/cm². The electrons were accelerated by the LINAC of the Naval Postgraduate School. The most probable energy losses agree with the theory ofBlunck andWestphal for all thicknesses; the half widths of the distributions agree with theory except for large thicknesses, where they exceed the theoretical values. These results are in contrast to those ofBreuer, which indicate systematically large half widths and most probable energy losses which are greater than theory for thicknesses greater than about 2 gm/cm². Since our data agree with those ofBreuer, the difference occurs in the treatment of the theory.     

The electrons of 2-D system in strong magnetic field and fractionally quantized Hall effect

This paper presents a limitation on the eigenvalues of angular momentum with the degeneracy of Landau level. According to the limitation a series of wave functions are given. In the case of few-body our calculations show that the Laughlin's Jastrow function are correct. This paper suggests wave functions to explain the fractionally quantized Hall effect.     

K-shell ionization by high energy electrons

It is shown that the data of Middleman, Ford and Hofstader on K-shell ionization by electrons with energy from 150 to 900 MeV is fit very well by a relativistic form of Bethe's theory of ionization.     

The optimization of electrostatic energy selection systems for low energy electrons

Design criteria are presented which allow electrostatic energy selection systems to be optimized to give the highest currents for electron beams having a low mean energy (? 500 eV) and a small energy spread (? 30 meV). Limitations in various parts of the system are discussed and a relationship between the current delivered by the system and the energy spread is presented. Different types and sizes for the energy selectors in these systems are considered and the best results are obtained with hemispherical deflectors. The advantage of using, within reasonable limits, a large selector with small image sizes is also demonstrated.     

The measured energy loss of high energy electrons in various metals

The energy distribution of electrons of about 53, 75 and 93 MeV has been measured before and after passing through Be, Sn and Gd absorbers of various thicknesses. Earlier data for Al, Cu and Pb absorbers are reviewed. The electrons were accelerated by the LINAC of the Naval Postgraduate School. The most probable energy loss and the half widths agree with the theory of Blunck and Westphal. An improved semi-empirical formula for the most probable energy loss is presented.     

Correlation function of electrons in a magnetic field

The influence of a magnetic field on the correlation function of conduction electrons in metals at zero temperature is examined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 91–94, August, 1972.     

高能电子束韧致辐射特性的理论研究

高能电子束轰击金属靶会产生韧致辐射X射线,为优化韧致辐射X射线品质,需要研究如何获取最佳辐射效率等韧致辐射规律.结合理论分析,并采用MCNP/4C对10,20?MeV电子的韧致辐射规律进行了模拟研究.讨论了不同靶材料产生的韧致辐射效率、角分布、能谱分布、准直锥孔内辐射效率等问题.通过对不同靶材料韧致辐射的模拟研究,给出了不同厚度靶与光子效率、注量分布、出射电子与角分布的关系与规律.由此得到不同靶材料对于10,20?MeV电子在最优韧致辐射效率下的一些边界条件与规律. 关键词： 韧致辐射 最佳效率 角分布 能谱