2023-08-09 ペンシルベニア州立大学(PennState)
◆強誘電材料は、音波、インクジェットプリンター、エネルギー効率の高いRAM、スマートフォンのジャイロスコープなどに応用される独特の特性を持ちます。従来の予測手法ではパラメータ調整が必要でしたが、Zentropy理論はそのような調整をせずに実験結果を予測することができるとされています。これにより研究効率が向上し、時間とエネルギーの節約に寄与するとともに、強誘電材料の探索が効果的に行える可能性があります。
＜関連情報＞
- https://www.psu.edu/news/materials-research-institute/story/zentropy-and-art-creating-new-ferroelectric-materials/
- https://www.sciencedirect.com/science/article/abs/pii/S135964622300204X
量子力学と統計力学の組み合わせによるPbTiO3の相転移のパラメータフリー予測 Parameter-free prediction of phase transition in PbTiO3 through combination of quantum mechanics and statistical mechanics
Zi-Kui Liu, Shun-Li Shang, Jinglian Du, Yi Wang
Scripta Materialia Available online: 20 April 2023
DOI:https://doi.org/10.1016/j.scriptamat.2023.115480
Abstract
Thermodynamics of ferroelectric materials and their ferroelectric to paraelectric (FE-PE) transitions is commonly described by the phenomenological Landau theory and more recently by effective Hamiltonian and various potentials, all with model parameters fitted to experimental or theoretical data. Here we show that the zentropy theory, which considers the total entropy of a system as a weighted sum of entropies of configurations that the system may experience and the statistical entropy among the configurations, can predict the FE-PE transition without fitting parameters. For PbTiO3, the configurations are identified as the FE configurations with 90- or 180° domain walls in addition to the ground state FE configuration without domain wall. With the domain wall energies predicted from first-principles based on density functional theory in the literature as the only inputs, the FE-PE transition for PbTiO3 is predicted showing remarkable agreement with experiments, unveiling the microscopic fundamentals of the transition.
