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# Search results

50 records were found.

## Anomalous robustness of the 5/2 fractional quantum Hall state near a sharp phase boundary

We report magneto-transport measurements in wide GaAs quantum wells with tunable density to probe the stability of the fractional quantum Hall effect at filling factor $\nu =$ 5/2 in the vicinity of the crossing between Landau levels (LLs) belonging to the different (symmetric and antisymmetric) electric subbands. When the Fermi energy ($E_F$) lies in the excited-state LL of the symmetric subband, the 5/2 quantum Hall state is surprisingly stable and gets even stronger near this crossing, and then suddenly disappears and turns into a metallic state once $E_F$ moves to the ground-state LL of the antisymmetric subband. The sharpness of this disappearance suggests a first-order transition.

## Observation of reentrant quantum Hall states in the lowest Landau level

Measurements in very low disorder two-dimensional electrons confined to relatively wide GaAs quantum well samples with tunable density reveal reentrant $\nu=1$ integer quantum Hall states in the lowest Landau level near filling factors $\nu=4/5$ and 6/5. These states are not seen at low densities and become more prominent with increasing density and in wider wells. Our data suggest a close competition between different types of Wigner crystal states near these fillings. We also observe an intriguing disappearance and reemergence of the $\nu=4/5$ fractional quantum Hall effect with increasing density.

## Spin Transition in the \nu=8/3 Fractional Quantum Hall Effect

Comment: Accepted for publication in Phys. Rev. Lett

## Spin and charge distribution symmetry dependence of stripe phases in two-dimensional electron systems confined to wide quantum wells

Measurements in clean two-dimensional electron systems confined to wide GaAs quantum wells in which two electric subbands are occupied reveal an unexpected rotation of the orientation of the stripe phase observed at a half-filled Landau level. Remarkably, the reorientation is sensitive to the spin of the half-filled Landau level and the symmetry of the charge distribution in the quantum well.

## Hole-flux Composite Fermion Commensurability Oscillations

Comment: 5 pages, 3 figures

## Spin Susceptibility of an Ultra-Low Density Two Dimensional Electron System

Comment: 5 pages, 2 eps figures, to appear in PRL

## Cascade of Quantum Phase Transitions in Tunnel-Coupled Edge States

Comment: 4 pages, 3 figures

## High mobility two-dimensional hole system in GaAs/AlGaAs quantum wells grown on (100) GaAs substrates

Comment: submitted to Applied Physics Letters

## Interaction Effects and Pseudogap in Two-Dimensional Lateral Tunnel Junctions

Comment: 5 pages, 4 figures

## Large Bychkov-Rashba spin-orbit coupling in high-mobility GaN/AlGaN heterostructures

Comment: Accepted for publication in PRB