Muonium centers in GaAs and GaP

The authors present the first observation of muon spin rotation for normal (Mu) and anomalous (Mu*) muonium centers in compound semiconductors, specifically GaP and GaAs. As in the elemental semiconductors, the muonium defect centers are characterized by a large isotropic hyperfine interaction for Mu but by a small, highly anisotropic, 111symmetric hyperfine interaction for Mu*. All hyperfine parameters measured in GaAs are remarkably close to those obtained in GaP. Furthermore, Apara* is greater than A* for Mu*. These last results are in marked contrast with the observations in diamond, Si, and Ge. © 1985 The American Physical Society.