Search

The contribution of the electron-electron interaction to conductivity is analyzed step by step in gated GaAs/InGaAs/GaAs heterostructures with different starting disorder. We demonstrate that the diffusion theory works down to $k_F l\simeq 1.5-2$, where $k_F$ is the Fermi quasimomentum, $l$ is the mean free paths. It is shown that the e-e interaction gives smaller contribution to the conductivity than the interference independent of the starting disorder and its role rapidly decreases with $k_Fl$ decrease., Comment: 5 pages, 6 figures

The quantum correction to the conductivity have been studied in two types of 2D heterostructures: with doped quantum well and doped barriers. The consistent analysis shows that in the structures where electrons occupy the states in quantum well only, all the temperature and magnetic field dependencies of the components of resistivity tensor are well described by the theories of quantum corrections. The contribution of electron-electron interaction to the conductivity have been determined reliably in the structures with different electron density. A possible reason of large scatter in experimental data concerning the contribution of electron-electron interaction, obtained in previous papers, and the role of the carriers, occupied the states of the doped layers, is discussed., Comment: 10 pages with 9 figures

The weak localization correction to the conductivity in coupled double layer structures is studied both experimentally and theoretically. Statistics of closed paths has been obtained from the analysis of magnetic field and temperature dependencies of negative magnetoresistance for magnetic field perpendicular and parallel to the structure plane. The comparison of experimental data with results of computer simulation of carrier motion over two 2D layers with scattering shows that inter-layers transitions play decisive role in the weak localization., Comment: 5 PRB pages with 5 eps-figures, submitted to Phys.Rev.B

It is shown that a new kind of information can be extracted from the Fourier transform of negative magnetoresistance in 2D semiconductor structures. The procedure proposed provides the information on the area distribution function of closed paths and on the area dependence of the average length of closed paths. Based on this line of attack the method of analysis of the negative magnetoresistance is suggested. The method has been used to process the experimental data on negative magnetoresistance in 2D structures with different relations between the momentum and phase relaxation times. It is demonstrated this fact leads to distinction in the area dependence of the average length of closed paths., Comment: 5 pages, 5 figures, to be published in Phys.Rev.B

It is shown that a new kind of information can be extracted from the Fourier transform of negative magnetoresistance (MR) in 2D semiconductor structures. The procedure proposed provides the information on the area distribution function of the closed paths and on the area dependence of the mean length of closed paths $\bar{L} (S)$ . Based on this line of attack the method of analysis of the negative MR is suggested. The method is used for data treatment of negative MR in 2D structures. In previous version (cond-mat/9902038) we suppoused that the difference in area dependence of $\bar{L} (S)$ for structures investigated came from the difference in scattering ansotropy. The more detailed analysis shows that main reason for such difference is different relations between momentum and phase relaxation times., Comment: This paper has been significantly modified and placed in cond-mat/9912431

There was shown that Fourier transform of the negative magnetoresistance (NMR) which is due to interference correction to the conductivity contains the information about the area distribution function of the closed paths and about area dependence of the mean length of closed paths \bar{L}(S). Based on this line of attack we suggest the method of analysis of NMR and use it for data treatment of the NMR in 2D structure with doped barrier. There was shown that in structure investigated \bar{L}(S)dependence is determined by the scattering anisotropy., Comment: PostScript-format with figures