Exploring low-temperature structures in fluorite-structured oxides

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04648
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26020:Inorganic materials and properties-related
• Research Institution: Japan Fine Ceramics Center
• Principal Investigator: Ogawa Takafumi 一般財団法人ファインセラミックスセンター, その他部局等, 上級研究員 (90515561)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 第一原理計算 / 結晶構造探索 / 機械学習ポテンシャル / モンテカルロ法 / 蛍石構造

Outline of Final Research Achievements

In this study, theoretical analysis methods are developed for investigating the cooling-rate-dependent local ordering phenomena and related physical properties observed in fluorite-type derived structures. We applied the configuration search method which combines first-principles calculations, neural network potentials, and Monte Carlo thermodynamic sampling, to clarify the existence of temperature-dependent local structural changes in complex oxide crystals. We also proposed methods to analyze physical properties such as oxygen ion diffusivity and point defect behavior, and applied it to systems with pyrochlore and fluorite-type structures. As described above, we have established the basis of methods to investigate low-temperature structures that do not have a clear long-range order.

Free Research Field

材料計算

Academic Significance and Societal Importance of the Research Achievements

本研究で開発された手法を用いることで、中性子全散乱測定に基づくPDF解析や冷却速度の低下により複合酸化物結晶中に存在が示唆される局所秩序状態と、その材料特性を理論的に調べることができる。イオン伝導性や電子・光物性等の材料特性は局所構造の変化に影響を受けるため、上記の理論解析より、機能性材料の探索や制御をする上で必要となる基礎的な情報を得ることができる。よって、様々なエネルギー材料の開発に役立てられるものと期待される。