First-principles study of location of Er³⁺ ion - Relationship to understanding of hyperfine interactions in the optoelectronic erbium-silicon system

The importance of hyperfine interactions in the Erbium-Silicon system is underscored by our first-principles Hartree-Fock Cluster investigations on the location of Erbium in Silicon. Our theoretical studies show that both substitutional and tetrahedral interstitial sites are stable for Er ^{3 +} ion with the latter having a larger binding energy. This conclusion is not completely supported by channeling experiments. It is suggested that Mössbauer measurements on ¹⁶⁶Er isotope would be valuable to compare experimental results with theoretical predictions of the hyperfine interactions of both magnetic and quadrupolar types to provide additional information about the location of Er³⁺.