Local Electronic Structure and Dynamics of Muon-Polaron Complexes in Fe${}_2$O${}_3$

Abstract

We perform detailed muon spin rotation ($\mu$SR) measurements in the classic antiferromagnet Fe${}_2$O${}_3$ and explain the spectra by considering dynamic population and dissociation of charge-neutral muon-polaron complexes. We show that charge-neutral muon states in Fe${}_2$O${}_3$, 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 Fe${}_2$O${}_3$ suggests that isolated hydrogen (H) impurities form analogous complexes, and that H interstitials may be a source of charge carrier density in Fe${}_2$O${}_3$.

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• The rust challenge -- On the correlations between electronic structure, excited state dynamics and photoelectrochemical performance of hematite photoanodes for solar water splitting
• Polaronic nature of a muonium-related paramagnetic center in SrTiO${}_3$