DETERMINATION OF LANDAU LEVEL LIFETIMES IN n-GaAs

DETERMINATION OF LANDAU LEVEL LIFETIMES IN n

Robust fractional quantum Hall effect in the N=2 Landau level in bilayer graphene

The fractional quantum Hall effect is a canonical example of electron-electron interactions producing new ground states in many-body systems. Most fractional quantum Hall studies have focussed on the lowest Landau level, whose fractional states are successfully explained by the composite fermion model. In the widely studied GaAs-based system, the composite fermion picture is thought to become u...

Composite fermions and Landau-level mixing in the fractional quantum Hall effect.

The reduction of the energy gap due to Landau level mixing, characterized by the dimensionless parameter λ = (e/ǫl0)/h̄ωc, has been calculated by variational Monte Carlo for the fractional quantum Hall effect at filling fractions ν = 1/3 and 1/5 using a modified version of Jain’s composite fermion wave functions. These wave functions exploit the Landau level mixing already present in composite f...

- m at . m es - h al l ] 2 4 A pr 1 99 7 Critical Behavior of Nuclear - Spin Diffusion in GaAs / AlGaAs Heterostructures near Landau Level Filling ν = 1

Thermal measurements on a GaAs/AlGaAs heterostructure reveal that the state of the confined two-dimensional electrons dramatically affects the nuclear-spin diffusion near Landau level filling factor ν=1. The experiments provide quantitative evidence that the sharp peak in the temperature dependence of heat capacity near ν=1 is due to an enhanced nuclear-spin diffusion from the GaAs quantum well...

POWER BROADENING AND NONLINEAR FIR MAGNETO-PHOTOCONDUCTIVITY IN n-GaAs

The saturation of the photoconductivity due to Is-2p+ shallow donor transitions in n-GaAs has been investigated using a high power cw-FIR-laser. Magnetic field strengths were chosen in such a way that 2p+ energy levels were either below or above the N = O conduction band Landau level. In the former case Is-2p+ transitions are found to be inhomogeneously broadened with a saturation intensity as ...