An electron-paramagnetic-resonance (EPR) investigation of silicon doped with gallium and manganese shows a defect-related spectrum with trigonal symmetry. The proof that Mn and Ga are involved in the defect is based on the observed hyperfine interactions. A complicated fine-structure behavior results from the fact that the zero-field and Zeeman splittings are of similar magnitude, a so-called intermediate case. The analysis of the experimental data gives strong evidence that the defect is a nearest-neighbor pair of interstitial Mn and substitutional Ga, and that the EPR spectrum originates from the ${}_{}{}^6{}_{}{}^{}$${\mathit{S}}_{5/2}$ ground state of the ${\mathrm{Mn}}^{2+}$ ion in a crystal field of tetrahedral symmetry with a strong trigonal distortion, i.e., from a (${\mathrm{Mn}}_{\mathit{i}}^{2+}$${\mathrm{Ga}}_{\mathit{s}}^{\mathrm{-}}$) pair. A comparison between different Mn-acceptor pairs suggests that the size of the pairing acceptor is the main reason for the observed differences in the strength of the trigonal zero-field splitting.

• Received 30 January 1991

DOI:https://doi.org/10.1103/PhysRevB.44.3678