8Li in GaAs studied with β-NMR

Abstract β -NMR has been used to study isolated spin polarized Li + 8 in bulk crystalline GaAs. At low temperatures a large fraction (at least 70%) of the Li end up in locations with cubic symmetry (e.g. a tetrahedral interstitial site). The linewidth of the β -NMR Li + 8 resonance increases dramatically above 150 K, and reaches a maximum at about 290 K. These results are consistent with a site change from an interstitial to a substitutional beginning at ≈ 150 K . The field dependence of the linewidth at 100 K is also discussed.