Local Electronic Structure And Dynamics Of Muon-Polaron Complexes In Fe2o3

We perform detailed muon spin rotation (mu SR) measurements in the classic antiferromagnet Fe2O3 and explain the spectra by considering dynamic population and dissociation of charge-neutral muon-polaron complexes. We show that charge-neutral muon states in Fe2O3, despite lacking the signatures typical of charge-neutral muonium centers in nonmagnetic materials, have a significant impact on the measured mu SR frequencies and relaxation rates. Our identification of such polaronic muon centers in Fe2O3 suggests that isolated hydrogen (H) impurities form analogous complexes, and that H interstitials may be a source of charge carrier density in Fe2O3