Study of the Electronic State of Hydrogen by a Combination of the Muon as Pseudo Hydrogen and First-Principles Calculation

Abstract

We investigated the electronic states of hydrogen in the transparent oxide semiconductor InGaZnO₄ (IGZO) using elementary particle muons (Mu) as a light isotope of hydrogen. From the combination of the relaxation rate Δ in Kubo-Toyabe function observed by the muon spin rotation method and the simulation of hydrogen by the first-principles calculation, it was clarified that the muon in the crystalline IGZO and the amorphous thin film IGZO occupies Zn-O bind center position. By analogy with ZnO, it is suggested that the corresponding hydrogen acts as a donor. In contrast, Lorentz-type spectra observed in the hydrogenated thin film IGZO show that some muons exist as Mu⁻H⁻ at oxygen vacancy positions.