Probing the shallow-donor muonium wave function in ZnO and CdS via transferred hyperfine interactions

Abstract

The assignment of muon spin rotation spectra to muonium counterparts of hydrogen shallow-donor states is reviewed in four II-VI widegap semiconductors, CdS, CdSe, CdTe and ZnO. The existence of extended electronic orbitals is argued from the muon-electron hyperfine parameters and supported by the new muon spin repolarization data for CdS and ZnO, characterizing the superhyperfine parameters on the sparse Cd and Zn dipolar nuclei. The possibility of a more tightly bound electron occupying a compact orbital is reasonably excluded in these materials, contrasting with the muonium state in HgO.