Shin Ilgyou, Carter Emily A
Department of Chemistry, Princeton University, Princeton, New Jersey 08544-1009, USA.
Department of Mechanical and Aerospace Engineering, Program in Applied and Computational Mathematics, and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544-5263, USA.
J Chem Phys. 2014 May 14;140(18):18A531. doi: 10.1063/1.4869867.
We propose a new form of orbital-free (OF) kinetic energy density functional (KEDF) for semiconductors that is based on the Wang-Govind-Carter (WGC99) nonlocal KEDF. We enhance within the latter the semi-local von Weizsäcker KEDF term, which is exact for a single orbital. The enhancement factor we introduce is related to the extent to which the electron density is localized. The accuracy of the new KEDF is benchmarked against Kohn-Sham density functional theory (KSDFT) by comparing predicted energy differences between phases, equilibrium volumes, and bulk moduli for various semiconductors, along with metal-insulator phase transition pressures. We also compare point defect and (100) surface energies in silicon for a broad test of its applicability. This new KEDF accurately reproduces the exact non-interacting kinetic energy of KSDFT with only one additional adjustable parameter beyond the three parameters in the WGC99 KEDF; it exhibits good transferability between semiconducting to metallic silicon phases and between various III-V semiconductors without parameter adjustment. Overall, this KEDF is more accurate than previously proposed OF KEDFs (e.g., the Huang-Carter (HC) KEDF) for semiconductors, while the computational efficiency remains at the level of the WGC99 KEDF (several hundred times faster than the HC KEDF). This accurate, fast, and transferable new KEDF holds considerable promise for large-scale OFDFT simulations of metallic through semiconducting materials.
我们基于Wang-Govind-Carter（WGC99）非局部动能密度泛函（KEDF），提出了一种适用于半导体的新型无轨道（OF）动能密度泛函。我们在后者的基础上增强了半局部的冯·魏茨泽克KEDF项，该项对于单个轨道是精确的。我们引入的增强因子与电子密度的局域程度有关。通过比较各种半导体不同相之间的预测能量差、平衡体积和体模量以及金属-绝缘体相变压力，将新KEDF的精度与Kohn-Sham密度泛函理论（KSDFT）进行基准测试。我们还比较了硅中的点缺陷和（100）表面能，以广泛测试其适用性。这种新KEDF仅在WGC99 KEDF的三个参数之外增加了一个可调参数，就能准确再现KSDFT的精确非相互作用动能；它在半导体到金属硅相之间以及各种III-V族半导体之间表现出良好的可转移性，无需调整参数。总体而言，对于半导体，这种KEDF比先前提出的OF KEDF（例如Huang-Carter（HC）KEDF）更准确，而计算效率保持在WGC99 KEDF的水平（比HC KEDF快数百倍）。这种准确、快速且可转移的新KEDF对于从金属到半导体材料的大规模OFDFT模拟具有很大的前景。
