Unusual Landau level pinning and correlated ν = 1 quantum Hall effect in hole systems confined to wide GaAs quantum wells.

In two-dimensional hole systems confined to wide GaAs quantum wells, where the heavy- and light-hole states are close in energy, we observe a very unusual crossing of the lowest two Landau levels as the sample is tilted in a magnetic field. At a magic tilt angle θ ≃ 34°, which surprisingly is independent of the well width or hole density, in a large filling factor range near ν = 1, the lowest two levels are nearly degenerate as evidenced by the presence of two-component quantum Hall states. Remarkably, a quantum Hall state is seen at ν = 1, consistent with a correlated Ψ111 state. [ABSTRACT FROM AUTHOR]