A variational method for density functional theory calculations on metallic systems with thousands of atoms
A variational method for density functional theory calculations on metallic systems with thousands of atoms
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DOI：
10.1063/1.4817001
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发表时间：
2013-08-07
影响因子：
4.4
通讯作者：
Skylaris, Chris-Kriton
中科院分区：
文献类型：
--
作者：
Ruiz-Serrano, Alvaro;Skylaris, Chris-Kriton
提出了一种新的有限温度密度泛函理论计算方法，该方法大大增加了金属体系中可以模拟的原子数。一个自洽的，直接最小化技术是用来获得亥姆霍兹自由能的电子系统中，描述的一组非正交的，本地化的功能，在原位优化使用一个双正弦基组，相当于平面波。计算的大多数部分，包括建立哈密顿矩阵的苛刻操作，都具有与系统中原子数量线性相关的计算成本。此外，这种方法确保了哈密顿矩阵具有最小的大小，这减少了由于对角化而导致的计算开销，对角化是仍然需要的缩放操作。通过局部化函数的优化保留了大基组精度。这种方法可以准确模拟整个金属纳米结构，并通过对具有500个原子的块体铜超级电池和具有多达2057个原子的金纳米颗粒的计算来证明。(C)2013 AIP Publishing LLC.
A new method for finite-temperature density functional theory calculations which significantly increases the number of atoms that can be simulated in metallic systems is presented. A self-consistent, direct minimization technique is used to obtain the Helmholtz free energy of the electronic system, described in terms of a set of non-orthogonal, localized functions which are optimized in situ using a periodic-sinc basis set, equivalent to plane waves. Most parts of the calculation, including the demanding operation of building the Hamiltonian matrix, have a computational cost that scales linearly with the number of atoms in the system. Also, this approach ensures that the Hamiltonian matrix has a minimal size, which reduces the computational overhead due to diagonalization, a cubic-scaling operation that is still required. Large basis set accuracy is retained via the optimization of the localized functions. This method allows accurate simulations of entire metallic nanostructures, demonstrated with calculations on a supercell of bulk copper with 500 atoms and on gold nanoparticles with up to 2057 atoms. (C) 2013 AIP Publishing LLC.