We report on the stability and magnetic state of ion implanted 8Li in single crystals of the semiconductor ZnO using β-detected nuclear magnetic resonance. At ultradilute concentrations, the spectra reveal distinct Li sites from 7.6 to 400 K. Ionized shallow donor interstitial Li is stable across the entire temperature range, confirming its ability to self-compensate the acceptor character of its (Zn) substitutional counterpart. Above 300 K, spin-lattice relaxation indicates the onset of correlated local motion of interacting defects, and the spectra show a site change transition from disordered configurations to substitutional. Like the interstitial, the substitutional shows no resolved hyperfine splitting, indicating it is also fully ionized above 210 K. The electric field gradient at the interstitial 8Li exhibits substantial temperature dependence with a power law typical of non-cubic metals.
@article{arxiv.2109.08637,
title = {Nuclear magnetic resonance of ion implanted $^8$Li in ZnO},
author = {Jonah R. Adelman and Derek Fujimoto and Martin H. Dehn and Sarah R. Dunsiger and Victoria L. Karner and C. D. Philip Levy and Ruohong Li and Iain McKenzie and Ryan M. L. McFadden and Gerald D. Morris and Matthew R. Pearson and Monika Stachura and Edward Thoeng and John O. Ticknor and Naoki Ohashi and Kenji M. Kojima and W. Andrew MacFarlane},
journal= {arXiv preprint arXiv:2109.08637},
year = {2022}
}