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Despite the fact that the problem of interference mechanism of magnetoresistance in semiconductors with hopping conductivity was widely discussed, most of existing studies were focused on the model of spinless electrons. This model can be justified only when all electron spins are frozen. However there is always an admixture of free spins in the semiconductor. This study presents the theory of interference contribution to magnetoresistance that explicitly includes effects of both frozen and free electron spins. We consider the cases of small and large number of scatterers in the hopping event. For the case of large number of scatterers the approach is used that takes into account the dispersion of the scatterer energies. We compare our results with existing experimental data.
We predict the universal power law dependence of localization length on magnetic field in the strongly localized regime. This effect is due to the orbital quantum interference. Physically, this dependence shows up in an anomalously large negative mag
We have studied the AC response of a hopping model in the variable range hopping regime by dynamical Monte Carlo simulations. We find that the conductivity as function of frequency follows a universal scaling law. We also compare the numerical result
We investigate the magneto-conductance (MC) anisotropy in the variable range hopping regime, caused by quantum interference effects in three dimensions. When no spin-orbit scattering is included, there is an increase in the localization length (as in
We develop a theory of magnetoresistance based on variable-range hopping. An exponentially large, low-field and necessarily positive magnetoresistance effect is predicted in the presence of Hubbard interaction and spin-dynamics under certain conditio
Effects of strong electric fields on hopping conductivity are studied theoretically. Monte-Carlo computer simulations show that the analytical theory of Nguyen and Shklovskii [Solid State Commun. 38, 99 (1981)] provides an accurate description of hop