Transport and tunneling within a compressible electron liquid in wires andrings of GaAs/AlxGa1-xAs heterostructures

A detailed study of low-temperature magnetoconductance in between v=2 and v =3 quantized Hall plateaus is presented. The data are obtained for disorder ed two-terminal submicron wires and rings defined in GaAs/A1(x)Ga(1-x)As he terostructures modulation doped by Si. In the region between the plateaus, electron density of compressible liquid in the central current strip increa ses gradually when lowering the magnetic field. At low densities of the ele ctrons in the strip, a sequence of peaks is detected in the dependence of c onductance on the magnetic field. This unexpected effect is interpreted in terms of the Coulomb blockade associated with the charging of the current s trip. In the same range of the magnetic fields, a temperature dependence of conductance, together with the absence of the Aharonov-Bohm oscillations f or transport along the central strip in the ring, are taken as the evidence for an enhancement of the electron-phonon scattering rate at the percolati on threshold. The frequency doubling of the Aharonov-Bohm oscillations in a ring with an additional potential barrier is discussed in terms of the pha se concept. Slow time evolution of conductance is observed for higher conce ntrations of the electrons in the current strip. This surprising noise is a ttributed to glassy dynamics of localized electrons in the wire center, and to the corresponding time dependence of the impurity-assisted tunneling pr obability between the current carrying regions. [S0163-1829(98)03548-6].