Elemental vacancy diffusion database from high-throughput first-principles calculations for fcc and hcp structures
Elemental vacancy diffusion database from high-throughput first-principles calculations for fcc and hcp structures
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DOI：
10.1088/1367-2630/16/1/015018
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发表时间：
2014-01-13
影响因子：
3.3
通讯作者：
Morgan, Dane
中科院分区：
文献类型：
--
作者：
Angsten, Thomas;Mayeshiba, Tam;Morgan, Dane
这项工作展示了如何从高通量从头计算中开发与扩散相关的属性数据库。用从头算方法计算了面心立方(FCC)和六方密排(HCP)晶体结构中所有足够稳定的纯元素空位的形成能和迁移能。对于HCP的迁移，同时考虑了基面和z方向最近邻空位跃迁。成功地计算了fcc结构中的49个元素和hcp结构中的44个元素的能垒。为了发现显著的相关性，我们将这些数据与各种元素性质进行了对比。计算的数据与门捷列夫数字对比时，显示出平稳而连续的趋势。空位形成能与内聚能的关系曲线呈线性趋势，fcc和hcp结构的回归斜率分别为0.317和0.323。这一结果表明，成键越强，空位形成能越高。斜率约为0.3，远低于一个简单的固定键强模型所预测的斜率，这与多体效应和弛豫导致的空位形成能的降低是一致的。发现空位迁移势垒随着硬度的增加近似线性地增加，这与原子迁移所需的局域膨胀是一致的。建立了一个简单的半经验公式来预测fcc体系的空位迁移能，计算结果的误差约为30%。
This work demonstrates how databases of diffusion-related properties can be developed from high-throughput ab initio calculations. The formation and migration energies for vacancies of all adequately stable pure elements in both the face-centered cubic (fcc) and hexagonal close packing (hcp) crystal structures were determined using ab initio calculations. For hcp migration, both the basal plane and z-direction nearest-neighbor vacancy hops were considered. Energy barriers were successfully calculated for 49 elements in the fcc structure and 44 elements in the hcp structure. These data were plotted against various elemental properties in order to discover significant correlations. The calculated data show smooth and continuous trends when plotted against Mendeleev numbers. The vacancy formation energies were plotted against cohesive energies to produce linear trends with regressed slopes of 0.317 and 0.323 for the fcc and hcp structures respectively. This result shows the expected increase in vacancy formation energy with stronger bonding. The slope of approximately 0.3, being well below that predicted by a simple fixed bond strength model, is consistent with a reduction in the vacancy formation energy due to many-body effects and relaxation. Vacancy migration barriers are found to increase nearly linearly with increasing stiffness, consistent with the local expansion required to migrate an atom. A simple semi-empirical expression is created to predict the vacancy migration energy from the lattice constant and bulk modulus for fcc systems, yielding estimates with errors of approximately 30%.