The results of magnetoconductivity measurements in GaInAs quantum wells are presented. The observed magnetoconductivity appears due to the quantum interference, which lead to the weak localization effect. It is established that the details of the weak localization are controlled by the spin splitting of electron spectra. A theory is developed which takes into account both linear and cubic in electron wave vector terms in spin splitting, which arise due to the lack of inversion center in the crystal, as well as the linear terms which appear when the well itself is asymmetric. It is established that, unlike spin relaxation rate, contributions of different terms into magnetoconductivity are not additive. It is demonstrated that in the interval of electron densities under investigation ((0.98 − 1.85)·1012 cm −2 ) all three contribution are comparable and have to be taken into account to achieve a good agreement between the theory and experiment. The results obtained from comparison of the experiment and the theory have allowed us to determine what mechanisms dominate the spin relaxation in quantum wells and to improve the accuracy of determination of spin splitting parameters in A3B5 crystals and 2D structures. 73.20.Fz,73.70.Jt,71.20.Ej,72.20.My

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Pis'ma Zh. Eksp. Teor. Fiz. 33, No. 3, 152-155 (5 February 1981) The wave functions and spectra of complexes comprised of two or more electrons are determined for a two-dimensional case in the strong-field limit (the magnetic length is shorter than the effective Bohr radius). The electron complexes, which are localized in the charged impurity, are calculated. The spectra for the exciton and spin-wave excitations are obtained for a close-packed electron system (all the states of the lower Landau level are occupied).PACS numbers: 71.10. + x We present several quantum-mechanical results pertaining to the behavior of a two-dimensional electron system in a strong magnetic field. Lately, such a system has been intensively investigated mainly in connection with the two-dimensional Wigner crystal.' 1. We shall write the energy operator of the electron system in the gauge A x =-±.Hy, A y =±-Hx: H = H 0 +V, -r .), I-2 = eH/tc 2 i,k ' * where fi* is an effective magneton, which can be substantially greater than the Bohr magneton for a superconductor. We shall not concretely define the interaction now 143

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