2026-10-21 北海道大学,鳥取大学,科学技術振興機構
本研究の概念図。
＜関連情報＞
- https://www.hokudai.ac.jp/news/2026/10/602pd.html
- https://pubs.acs.org/nalefd/article-abstract/doi/10.1021/acs.nanolett.6c03635/5454869/Electron-Beam-Assisted-Formation-of-Simple-Cubic
電子線照射による単純立方構造をもつ銀結晶の生成 Electron-Beam-Assisted Formation of Simple-Cubic Silver
Masaya Sakakibara;Hiroki Nada;Yuji Kunisada;Tomoya Yamazaki;Yuki Kimura
Nano Letters Published:October 21, 2026
DOI:https://doi.org/10.1021/acs.nanolett.6c03635
Abstract
Accessing crystal phases under nonequilibrium conditions is a central challenge for expanding the landscape of materials. Simple-cubic (sc) structures are considered energetically unfavorable in elemental solids and have previously been confirmed only in polonium. Here, we report the direct observation of a previously unrecognized sc-Ag formed under far-from-equilibrium conditions. Using electron beam irradiation inside a high-resolution transmission electron microscope as a trigger, we induced the radiolytic decomposition of silver iodide (AgI) and tracked the in situ formation of silver crystals in real time. Continuous imaging revealed that sc-Ag formation strongly depends on the polymorph of the precursor and occurs selectively from metastable γ-AgI. The sc-Ag exhibited unusually high chemical reactivity, undergoing gradual oxidation into silver oxide under high-vacuum conditions where conventional fcc-Ag remains stable. These findings demonstrate that irreversible crystal formation pathways can kinetically stabilize crystal structures inaccessible under near-equilibrium conditions and extend a previously inaccessible structural limit of metallic bonding.
