The Influence of the Rashba spin orbit coupling on the two dimensional magnetoexcitons

Cataloged from PDF version of article.The influence of the Rashba spin-orbit coupling (RSOC) on the two-dimensional (2D) electrons and holes in a strong perpendicular magnetic field leads to different results for the Landau quantization in different spin projections. In the Landau gauge the unidimensional wave vector describing the free motion in one in-plane direction is the same for both spin projections, whereas the numbers of Landau quantization levels are different. For an electron in an s-type conduction band they differ by one, as was established earlier by Rashba (1960 Fiz. Tverd. Tela 2 1224), whereas for heavy holes in a p-type valence band influenced by the 2D symmetry of the layer they differ by three. The shifts and the rearrangements of the 2D hole Landau quantization levels on the energy scale are much larger in comparison with the case of conduction electron Landau levels. This is due to the strong influence of the magnetic field on the RSOC parameter. At sufficiently large values of this parameter the shifts and rearrangements are comparable with the hole cyclotron energy. There are two lowest spin-split Landau levels for electrons as well as four lowest ones for holes in the case of small RSOC parameters. They give rise to eight lowest energy bands of the 2D magnetoexcitons, as well as of the band-to-band quantum transitions. It is shown that three of them are dipole-active, three are quadrupole-active and two are forbidden. The optical orientation under the influence of circularly polarized light leads to optical alignment of the magnetoexcitons with different orbital momentum projections in the direction of the external magnetic field

Организация работы с персоналом при строительстве Обь-Енисейского канала в конце XIX в.

The article identifies areas of work with the staff practiced during the construction the Ob-Yenisei Canal, given their conformity assessment. Administration of the channel focused in working with staff on reducing costs and the intensification of work. Difficulties in HR were remoteness and difficult terrain, the labor shortage. The quality of work with the staff was on sufficient high-level  for the end of the XIX century.В статье выявляются направления работы с персоналом, практиковавшиеся при строительстве Обь-Енисейского канала, дается их оценка. Администрация канала при работе с персоналом ориентировалась на сокращение издержек и интенсификацию труда. Сложности в работе с персоналом составляли удаленность и труднодоступность местности, дефицит рабочей силы. Качество работы с персоналом было достаточно высоким для конца XIX века

On the theory of two-dimensional combined magnetoexciton-cyclotron resonances

A theory of combined exciton-cyclotron resonance in the quantum well structures is developed for a strong magnetic field. The absorption band structure is calculated for optical quantum transitions with circularly polarized radiation creating a two-dimensional exciton and simultaneously exciting one of the resident electrons from the lowest to the first Landau level. The dipole-active transitions are considered in the second-order perturbation theory taking into account as perturbations the electron-photon interaction and the electron-electron Coulomb interaction. In agreement with the experimental observation it is shown that for $\sigma ^{-}$ polarized light the probability of quantum transition is four times larger than for $\sigma ^{+}$ light polarization