Bayesian sparse modeling of extended x-ray absorption fine structure to determine interstitial oxygen positions in yttrium oxyhydride epitaxial thin film

Autor: Hiroyuki Kumazoe, Yasuhiko Igarashi, Fabio Iesari, Ryota Shimizu, Yuya Komatsu, Taro Hitosugi, Daiju Matsumura, Hiroyuki Saitoh, Kazunori Iwamitsu, Toshihiro Okajima, Yoshiki Seno, Masato Okada, Ichiro Akai
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: AIP Advances, Vol 11, Iss 12, Pp 125013-125013-5 (2021)
Druh dokumentu: article
ISSN: 2158-3226
DOI: 10.1063/5.0071166
Popis: This article presents a Bayesian sparse modeling method to analyze extended x-ray absorption fine structure (EXAFS) data with basis functions built on two-body signals. This method does not require any structural model and allows us to evaluate regression coefficients proportional to the radial distribution functions of the respective elements and their errors and is very effective for analysis of EXAFS with weak absorption intensity and severe signal-to-noise ratios. As an application example, we used it to analyze the EXAFS of an yttrium oxyhydride (YOxHy) epitaxial thin film. These EXAFS data show weak absorption intensity and a severe signal-to-noise ratio due to the small amount of x-ray absorption in the thin film sample. However, this approach revealed that the radial distance ratio of the second neighbor yttrium to the first neighbor oxygen coincides with that of a tetrahedral configuration. This result demonstrates that the interstitial oxygen position is tetrahedral in the YOxHy thin film.
Databáze: Directory of Open Access Journals