NMR in the solid phase of two-dimensional electrons at high magnetic fields

We report on a magnetic resonance study in the electron solid phase of a low-disorder GaAs/AlGaAs sample at very high magnetic fields using a resistively detected NMR technique. An anomalous dispersivelike line shape is observed at the onset of the electron solid in the vicinity of the Landau filling nu=2/9, 1/5 fractional quantum Hall state, reminiscent of the line shape observed near filling factor nu similar to 1. In contrast to this filling factor region, the spin-lattice relaxation time T-1 in the electron solid is found to be very long, and does not correlate with either R-xx or the Landau filling factor. The dispersivelike line shapes observed in this regime suggests that the intricate interplay between the nuclear spin and the electronic transport may be modified by the formation of the electron solid.