Observation of a reentrant insulating phase near the 1/3 fractional quantum Hall liquid in a two-dimensional hole system

In a dilute, low-disorder, two-dimensional IholeR system at the GaAs/AlGaAs heterointerface, we observe a reentrant insulating behavior around the =1/3 fractional quantum Hall liquid at B5 T, strikingly similar to recent observations in low-disorder 2D IelectronR systems near =1/5. We interpret this behavior as manifesting a weakly pinned hole Wigner crystal around =1/3, and suggest that its observation at such large is a result of Landau level mixing which, in the case of much heavier holes, significantly modifies the ground-state energies of the fractional quantum Hall and Wigner crystal states of the system.