2024-03-04 アルゴンヌ国立研究所(ANL)
＜関連情報＞
- https://www.anl.gov/article/scientists-shine-new-light-on-the-future-of-nanoelectronic-devices
- https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202305383
酸化物ヘテロ構造における断続的欠陥ゆらぎ Intermittent Defect Fluctuations in Oxide Heterostructures
Qingteng Zhang, Gang Wan, Vitalii Starchenko, Guoxiang Hu, Eric M. Dufresne, Hua Zhou, Hyoungjeen Jeen, Irene Calvo Almazan, Yongqi Dong, Huajun Liu, Alec R. Sandy …
Advanced Materials Published: 14 August 2023
DOI:https://doi.org/10.1002/adma.202305383
Abstract
The heterogeneous nature, local presence, and dynamic evolution of defects typically govern the ionic and electronic properties of a wide variety of functional materials. While the last 50 years have seen considerable efforts into development of new methods to identify the nature of defects in complex materials, such as the perovskite oxides, very little is known about defect dynamics and their influence on the functionality of a material. Here, the discovery of the intermittent behavior of point defects (oxygen vacancies) in oxide heterostructures employing X-ray photon correlation spectroscopy is reported. Local fluctuations between two ordered phases in strained SrCoOx with different degrees of stability of the oxygen vacancies are observed. Ab-initio-informed phase-field modeling reveals that fluctuations between the competing ordered phases are modulated by the oxygen ion/vacancy interaction energy and epitaxial strain. The results demonstrate how defect dynamics, evidenced by measurement and modeling of their temporal fluctuations, give rise to stochastic properties that now can be fully characterized using coherent X-rays, coupled for the first time to multiscale modeling in functional complex oxide heterostructures. The study and its findings open new avenues for engineering the dynamical response of functional materials used in neuromorphic and electrochemical applications.
