Optically detected nuclear magnetic resonance in n-GaAs using an on-chip microcoil

Optically detected nuclear magnetic resonance (NMR) with micrometer resolution is demonstrated in n-GaAs using an on-chip microcoil. To trace the Overhauser field, the electron Larmor frequency is monitored via time-resolved magneto-optical Kerr rotation. Sweeping the frequency of the rf magnetic field induced by an on-chip microscale current loop, nuclear spin depolarization is achieved for each isotope species. The experimental data indicate an impact of a local quadrupole field, most likely caused by ionized donors, on the amplitude and linewidth of the NMR spectrum. By applying rf pulse sequences, the Rabi oscillation of $A75s$ nuclear spins is obtained with an effective dephasing time of $∼200μs$⁠.