Muonium (Mu) centers formed upon implantation of μ+ in a solid have long been investigated as an experimentally accessible model of isolated hydrogen impurities. Recent discoveries of hydridic centers formed at oxygen vacancies have stimulated a renewed interest in H− and corresponding Mu− centers in oxides. However, the two diamagnetic centers, Mu+ and Mu−, are difficult to separate spectroscopically. In this review article, we summarize established and developing methodologies for identifying Mu− centers in solids, and review recent Mu studies on said centers supposedly formed in mayenite, oxygen-deficient SrTiO3−x, and BaTiO3−xHx oxyhydride.
@article{arxiv.2206.11478,
title = {Negatively Charged Muonium and Related Centers in Solids},
author = {Takashi U. Ito and Wataru Higemoto and Koichiro Shimomura},
journal= {arXiv preprint arXiv:2206.11478},
year = {2022}
}