2022 Fiscal Year Final Research Report

Theory of complex molecular systems: effective model and quantum dynamics

Research Project

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Project/Area Number	19K21860
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 13:Condensed matter physics and related fields
Research Institution	Institute of Physical and Chemical Research
Principal Investigator	Seo Hitoshi 国立研究開発法人理化学研究所, 開拓研究本部, 専任研究員 (30415054)
Co-Investigator(Kenkyū-buntansha)	圓谷貴夫熊本大学, 大学院先導機構, 助教 (00619869)
Project Period (FY)	2019-06-28 – 2023-03-31
Keywords	分子性結晶 / 第一原理計算 / 光誘起相転移 / 強相関電子系 / 量子ダイナミクス
Outline of Final Research Achievements	Targeting dynamics phenomena in molecular crystals, which are crystals composed of molecules, we have sought to understand the quantum dynamics of complex molecular systems by performing complementary first-principles calculations to construct microscopic effective models and real-time simulations for the effective models. Using novel first-principles methods for describing the electronic states of molecular crystals, we have succeeded in analyzing charge-ordered states, in which molecules with rich and poor charge densities spontaneously appear and align, and antiferromagnetic states, in which the spin magnetic moments appear periodically. In addition, to understand the phenomenon of charge ordering melting by irradiation of optical laser pulses, we simulated the time evolution of inhomogeneity using a quantum model and clarified the role of inhomogeneity for the first time.
Free Research Field	物性理論
Academic Significance and Societal Importance of the Research Achievements	電子物性研究の対象となりにくかった複雑な分子からなる結晶の電子状態の解析や、複数の相互作用が複雑に絡み合う光誘起応答を見せる分子性結晶の実時間シミュレーションを行うことにより、分子性結晶分野の新たな発展を促すことができた。近年発展してきた第一原理計算による定量的な有効モデル化の手法と、これに対する光応答実時間シミュレーションを組み合わせることにより、実験との比較まで到達し物質設計や機能創生にフィードバックを与えることができた。従来個々の問題として捉えられてきた課題に対して、固体物理、光物性物理、計算物理にまたがる異分野融合として位置付けられる。