2026-02-13 東京大学
粒子の詰まりやすさを表す、新しい秩序指標「局所的パッキング能」の最適化
＜関連情報＞
- https://www.rcast.u-tokyo.ac.jp/ja/news/release/20260213.html
- https://www.nature.com/articles/s41563-026-02496-8
対称性が破れない秩序状態の明確な形態としての理想的な非結晶 Ideal non-crystals as a distinct form of ordered states without symmetry breaking
Xinyu Fan,Ding Xu,Jianhua Zhang,Hao Hu,Peng Tan,Ning Xu,Hajime Tanaka & Hua Tong
Nature Materials Published:13 February 2026
DOI:https://doi.org/10.1038/s41563-026-02496-8
Abstract
Order and disorder are central concepts in condensed-matter physics. Crystals break translational and rotational symmetries, whereas quasicrystals challenge this paradigm with forbidden rotational symmetries and aperiodicity. Here we report a distinct ordered state—ideal non-crystals—characterized by optimal steric order without symmetry breaking. Steric optimization yields ideal non-crystals as a thermodynamically favoured limiting state, accompanied by maximal steric order that may serve as a true order parameter for the glass transition. Despite their apparent disorder, they exhibit long-range orientational correlations, quantified via a specific path-integral-like approach. Ideal non-crystals possess distinct properties, including Debye-like phononic modes, affine elasticity, thermodynamic ultrastability and long-wavelength density uniformity, reminiscent of hyperuniformity. By uncovering a distinct form of entropy-driven ordering in sterically optimized materials, this work expands the landscape of ordered states and provides a framework for designing amorphous materials with crystal-like mechanical and thermal properties free from the anisotropy inherent in crystals.
