We present a novel methodology to compute relaxed dislocations core configurations, and their energies in crystalline metallic materials using large-scale ab-intio simulations. The approach is based on MacroDFT, a coarse-grained density functional theory method that accurately computes the electronic structure with sub-linear scaling resulting in a tremendous reduction in cost. Due to its implementation in real-space, MacroDFT has the ability to harness petascale resources to study materials and alloys through accurate ab-initio calculations. Thus, the proposed methodology can be used to investigate dislocation cores and other defects where long range elastic defects play an important role, such as in dislocation cores, grain boundaries and near precipitates in crystalline materials. We demonstrate the method by computing the relaxed dislocation cores in prismatic dislocation loops and dislocation segments in magnesium (Mg). We also study the interaction energy with a line of Aluminum (Al) solutes. Our simulations elucidate the essential coupling between the quantum mechanical aspects of the dislocation core and the long range elastic fields that they generate. In particular, our quantum mechanical simulations are able to describe the logarithmic divergence of the energy in the far field as is known from classical elastic theory. In order to reach such scaling, the number of atoms in the simulation cell has to be exceedingly large, and cannot be achieved with the state-of-the-art density functional theory implementations.

我们提出了一种新颖的方法来计算弛豫位错的核心构型，以及使用大规模Ab-Intio模拟在晶体金属材料中的能量。该方法基于MacroDFT，MacroDFT是一种粗粒度的密度泛函理论方法，可以使用亚线性缩放精确地计算电子结构，从而大大降低了成本。由于其在现实空间中的实施，MacroDFT能够利用精确数据从头开始利用petascale资源来研究材料和合金。计算。因此，所提出的方法可用于研究位错核心和其他缺陷，其中远距离弹性缺陷起着重要作用，例如在位错核心，晶界和晶体材料中的近析出物中。我们通过计算棱柱形位错环和镁（Mg）中的位错段中的松弛位错核来演示该方法。我们还研究了与铝（Al）溶质线的相互作用能。我们的模拟阐明了位错核的量子力学方面与它们所产生的远距离弹性场之间的本质耦合。特别是，我们的量子力学模拟能够描述远场能量的对数发散，这是经典弹性理论所知道的。为了达到这样的规模，最新的密度泛函理论实现。