Sudoku-Inspired High-Shannon-Entropy Alloys
Sudoku-Inspired High-Shannon-Entropy Alloys
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DOI：
10.1016/j.actamat.2021.117556
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发表时间：
2021-10
期刊：
影响因子：
9.4
通讯作者：
H. Zhuang
中科院分区：
文献类型：
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作者：
H. Zhuang
目前高熵合金（HEA）的定义通常基于构型熵。但这个定义仅取决于 HEA 的化学成分，因此无法区分以各种局部原子排列编码并可通过信息论中的香农熵测量的信息内容。在这里，受到二维 (2D) 数独矩阵表现出比 2D 随机矩阵对应物更高的平均香农熵这一发现的启发，我们提出了高香农熵合金 (HSEA)，其结构基于 3D 数独矩阵。尽管形成 3D 数独 4 × 4 × 4 矩阵的原子排列受到限制，但我们发现，由于晶格畸变较小，原型 HSEA NbMoTaW 的能量比具有随机结构的相同 HEA 更低。我们计算了电子结构和机械性能，发现 HSEA 比随机 NbMoTaW HEA 表现出更高的平均费米速度和延展性。最后，我们评估了 HSEA 中单个空位和空位簇的形成能，其配置分别模拟具有一个和多个缺失数字的数独谜题。我们发现产生这种空位需要一系列大能量，这取决于缺失原子的位置和种类。我们的工作表明，将香农熵引入 HEA 提供了一个有用的度量来揭示 HEA 的更多原子细节，并且 HSEA 代表了 HEA 复杂能量景观中的未知领域，可能被赋予改进的性能。
Current definition of high-entropy alloys (HEAs) is commonly based on the configurational entropy. But this definition depends only on the chemical composition of a HEA and therefore cannot distinguish the information content that is encoded in various local atomic arrangements and measurable by the Shannon entropy in information theory. Here, inspired by the finding that two-dimensional (2D) Sudoku matrices exhibit higher average Shannon entropy than 2D random matrix counterparts, we propose high-Shannon-entropy alloys (HSEA), whose structures are based on 3D Sudoku matrices. Despite the constraints on the atomic arrangements to form a 3D Sudoku 4 × 4 × 4 matrix, we find that, a prototypical HSEA, NbMoTaW has a lower energy than the same HEA with a random structure due to the smaller lattice distortion. We compute the electronic structures and mechanical properties and find that the HSEA exhibits enhanced average Fermi velocity and ductility over the random NbMoTaW HEA. Finally, we evaluate the formation energies of single vacancies and a vacancy cluster in the HSEA, whose configurations mimic Sudoku puzzles with one and several missing numbers, respectively. We find that a range of large energies are required to generate such vacancies, which depend on the location and species of missing atoms. Our work shows that introducing the Shannon entropy to HEAs offers a useful metric to reveal more atomic details of HEAs and that HSEAs represent an uncharted domain in the complicated energy landscape of HEAs which may be endowed with improved properties.