Optically detected nuclear magnetic resonance of spatially selected lattice nuclei within a GaAs quantum well

The spectra of nuclear resonances provide a powerful microscopic probe of condensed matter, yet nuclear magnetic resonance (NMR) techniques have not so far been used to study semiconductor heterostructures. That is because only a tiny fraction of all the nuclei lie In the region of Interest, and conventional NMR cannot distinguish these. We report the first observation of optically detected NMR (ODNMR) of spatially selected nuclei In a semiconductor quantum well using an optical pumping technique which has the sensitivity and selectivity to overcome the limitations of conventional NMR. The sample is a 200 Angstrom thick single quantum well made p-type by applied electrical bias with a degenerate hole population of 10 11 cm -2 . The spectrum contains resonances corresponding to the three isotopes which make up the lattice: 69 Ga, 71 Ga, and 75 As. It differs strikingly from that reported for bulk GaAs in that there is a 60(7)-kHz quadrupole splitting of the 75 As resonance, shown In Fig. 1, which we attribute to the residual strain present in the GaAs layer.