2025-06-13 ミシガン大学
Image credit: Woohyeon Baek, Sun Research Group, University of Michigan
＜関連情報＞
- https://news.umich.edu/first-quantum-mechanical-model-of-quasicrystals-reveals-why-they-exist/
- https://www.nature.com/articles/s41567-025-02925-6
密度汎関数理論から見た準結晶の安定性と核生成速度論 Quasicrystal stability and nucleation kinetics from density functional theory
Woohyeon Baek,Sambit Das,Shibo Tan,Vikram Gavini & Wenhao Sun
Nature Physics Published:13 June 2025
DOI:https://doi.org/10.1038/s41567-025-02925-6
Abstract
The aperiodic order of quasicrystals bridges the amorphous and crystalline regime, so it has remained unclear whether quasicrystals are metastable or stable phases of matter. Density functional theory is often used to evaluate thermodynamic stability, but quasicrystals are long-range aperiodic and their energies cannot be calculated using conventional ab initio methods. Here, we perform first-principles calculations on quasicrystal nanoparticles of increasing size, from which we can directly extrapolate their bulk and surface energies. Using this technique, we determine with high confidence that the icosahedral quasicrystals ScZn7.33 and YbCd5.7 are ground-state phases, thus revealing that translational symmetry is not a necessary condition for the zero-temperature stability of inorganic solids. Although we found the ScZn7.33 quasicrystal to be thermodynamically stable, we show on a mixed thermodynamic and kinetic phase diagram that its solidification from the melt is limited by nucleation, which illustrates why even stable materials may be kinetically challenging to grow. Our techniques broadly open the door to first-principles investigations into the structure–bonding–stability relationships of aperiodic materials.
