Modelling radiation effects in solids with two-temperature molecular dynamics
Modelling radiation effects in solids with two-temperature molecular dynamics
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DOI：
10.1016/j.commatsci.2018.02.006
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发表时间：
2018-05
影响因子：
3.3
通讯作者：
Robert Darkins-;D. Duffy
中科院分区：
文献类型：
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作者：
Robert Darkins-;D. Duffy
如果能够预测各种辐照情景造成的材料结构变化，将对许多科学和技术领域产生积极影响。已建立的技术，如经典的分子动力学模拟大的原子系统，是有限的忽略电子自由度，限制其应用程序的辐射事件，主要是与原子核相互作用。另一方面，从头算方法包括电子自由度，但必要的计算成本限制了它们在相对较小的系统中的应用。最近的方法发展，旨在克服这些限制中的一些是基于耦合原子模型的电子能量，其中能量通过电子停止和电子-声子耦合机制的原子核和电子之间交换的连续模型的方法。这样的双温分子动力学模型，因为他们是已知的，使它切实可行的模拟电子激发的影响系统与数百万，甚至数亿，原子。它们已被用于研究激光照射的金属薄膜，快速重离子照射的金属和半导体，和适度高离子照射的金属。在这篇综述中，我们描述了两个温度的分子动力学方法和各种实际需要考虑的实施。我们提供的例子应用程序的模型，以适应电子激励的多个照射方案。我们还描述了挑战，包括修改的原子间相互作用的影响，由于电子的激发，在模拟和如何克服这些挑战。
The ability to predict the structural modifications of materials resulting from a broad range of irradiation scenarios would have a positive impact on many fields of science and technology. Established techniques for modelling large atomic systems, such as classical molecular dynamics, are limited by the neglect of the electronic degrees of freedom which restricts their application to irradiation events that primarily interact with atomic nuclei. Ab initio methods, on the other hand, include electronic degrees of freedom, but the requisite computational costs restrict their application to relatively small systems. Recent methodological developments aimed at overcoming some of these limitations are based on methods that couple atomistic models to a continuum model for the electronic energy, where energy is exchanged between the nuclei and electrons via electronic stopping and electron-phonon coupling mechanisms. Such two-temperature molecular dynamics models, as they are known, make it practicable to simulate the effects of electronic excitations on systems with millions, or even hundreds of millions, of atoms. They have been used to study laser irradiation of metallic films, swift heavy ion irradiation of metals and semiconductors, and moderately high ion irradiation of metals.In this review we describe the two-temperature molecular dynamics methodology and the various practical considerations required for its implementation. We provide example applications of the model to multiple irradiation scenarios that accommodate electronic excitations. We also describe the challenges of including the effects of the modification of the interatomic interactions, due to the excitation of electrons, in the simulations and how these challenges can be overcome.