论文标题
晶体缺陷的第一批原理研究的光谱正交：应用于镁
Spectral quadrature for the first principles study of crystal defects: Application to magnesium
论文作者
论文摘要
我们提出了一种准确有效的有限差分公式，并为嵌入在批量环境中的非周期系统的Kohn-Sham密度（运算符）功能理论（DFT）的平行实现。具体而言，采用非本地伪能力，静电的局部重新重新制定以及空间Kohn-Sham Hamiltonian的截断以及线性缩放频谱正交方法来求解真实空间中的点电子领域的点式电子领域，并为原子构建的非局部构建构建构造，我们在原子上构建了一个平行的构造，我们可以在原子上分配型号，以构建原子型的构造，以进行平行的记忆构造，嵌入在散装环境中。从镁 - 铝合金中选择实例，我们首先证明了相对于光谱正常多项式阶的能量和力的收敛性，以及空间截断的汉密尔顿的宽度。接下来，我们演示了框架的并行缩放，并证明计算时间和存储器比例相对于原子数线性。接下来，我们使用开发的框架模拟镁铝合金中的孤立点缺陷及其相互作用。我们的发现得出的结论是，DivaCances，Al溶质 - 脱水和两个Al溶质原子的结合能是各向异性的，并且取决于细胞的大小。此外，在所有三种情况下，结合均有利。
We present an accurate and efficient finite-difference formulation and parallel implementation of Kohn-Sham Density (Operator) Functional Theory (DFT) for non periodic systems embedded in a bulk environment. Specifically, employing non-local pseudopotentials, local reformulation of electrostatics, and truncation of the spatial Kohn-Sham Hamiltonian, and the Linear Scaling Spectral Quadrature method to solve for the pointwise electronic fields in real-space and the non-local component of the atomic force, we develop a parallel finite difference framework suitable for distributed memory computing architectures to simulate non-periodic systems embedded in a bulk environment. Choosing examples from magnesium-aluminum alloys, we first demonstrate the convergence of energies and forces with respect to spectral quadrature polynomial order, and the width of the spatially truncated Hamiltonian. Next, we demonstrate the parallel scaling of our framework, and show that the computation time and memory scale linearly with respect to the number of atoms. Next, we use the developed framework to simulate isolated point defects and their interactions in magnesium-aluminum alloys. Our findings conclude that the binding energies of divacancies, Al solute-vacancy and two Al solute atoms are anisotropic and are dependent on cell size. Furthermore, the binding is favorable in all three cases.
