2026-07-29 東京科学大学
図2. 6フェムト秒時間分解分光で観測した光照射直後の電子状態変化。（a）光照射後の過渡反射率変化スペクトル[用語9]。（b）零点交差エネルギー（（a）中の赤矢印）の時間変化。零点交差エネルギーは約30フェムト秒で急速に変化し、光誘起状態の超高速形成を示唆している。
＜関連情報＞
- https://www.isct.ac.jp/ja/news/1gklnnlerqz9#top
- https://journals.aps.org/prl/abstract/10.1103/x43y-61c1
金属有機構造体における結合次数波によって駆動される光誘起隠れ状態の超高速形成 Ultrafast Formation of a Photoinduced Hidden State Driven by a Bond-Order Wave in a Metal-Organic Framework
Samiran Banu, Tatsuya Amano, Takahisa Kato, Kou Takubo, Yoichi Okimoto, Shinya Koshihara, Yohei Kawakami, Hirotake Itoh, Wataru Kosaka
Physical Review Letters Publishe 22 July, 2026
DOI: https://doi.org/10.1103/x43y-61c1
Abstract
Sub-10-fs pump-probe reflectivity measurements combined with model calculations reveal the emergence of a photoinduced hidden (PH) state in a donor-acceptor-type metal-organic framework. Transient spectra exhibit an additional absorption band developing on a ≈30 fs timescale, signaling the ultrafast formation of the PH state. Time-frequency analysis captures spectral-weight transfer between phonons at ≈500 cm−1 and 600 cm−1, reflecting coherent oscillatory dynamics that accompany the formation of the PH state. Model calculations indicate that the PH state is a metastable polar state stabilized by bond-order-wave-driven lattice modulation, suggesting electronic ferroelectricity. These findings establish metal-organic frameworks as a versatile platform for exploring nonequilibrium quantum states.
