Search

It is shown that the observed Quantum Hall Effect in epitaxial layers of heavily doped n-type GaAs with thickness (50-140 nm) larger the mean free path of the conduction electrons (15-30 nm) and, therefore, with a three-dimensional single-particle spectrum is induced by the electron-electron interaction. The Hall resistance R_xy of the thinnest sample reveals a wide plateau at small activation energy E_a=0.4 K found in the temperature dependence of the transverse resistance R_xx. The different minima in the transverse conductance G_xx of the different samples show a universal temperature dependence (logarithmic in a large range of rescaled temperatures T/T_0) which is reminiscent of electron-electron-interaction effects in coherent diffusive transport., Comment: 6 pages, 3 figures, 1 table

We investigate the transport in a two-dimensional (2D) lattice of coupled Sinai billiards fabricated on the basis of a high-mobility 2D electron gas in GaAs/AlGaAs heterojunction. For the states with low reduced conductivity g<1 to g<, 8 pages, 3 figures. Submitted to Phys. Rev. Lett