Empirical interatomic potentials optimized for phonon properties (针对声子性能研究优化的经验性原子间相互作用势
Andrew Rohskopf,Hamid R. Seyf,Kiarash Gordiz,Terumasa Tadano&Asegun Henry
npj Computational Materials 3:27(2017)
doi:10.1038/s41524-017-0026-y
Published online:12 July 2017
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摘要:分子动力学模拟已被广泛用于研究并理解声子的性质,然而由于缺乏描述具体体系内部原子间相互作用的经验势函数(empirical interatomic potentials),模拟结果直接与实验数据比较通常比较困难,这已成为阻碍先进的原子水平模拟实际应用的主要障碍。本研究提出了一种通用方法,基于第一原理计算的结果作为输入,针对声子输运性能来研究优化经验性原子间相互作用势。本方法采用遗传算法,针对决定声子输运性能的一系列关键属性进行拟合,从而获得了相互作用经验势的参数。
Abstract: Molecular dynamics simulations have been extensively used to study phonons and gain insight, but direct comparisons to experimental data are often difficult, due to a lack of accurate empirical interatomic potentials for different systems. As a result, this issue has become a major barrier to realizing the promise associated with advanced atomistic-level modeling techniques. Here, we present a general method for specifically optimizing empirical interatomic potentials from ab initio inputs for the study of phonon transport properties, thereby resulting in phonon optimized potentials.The method uses a genetic algorithm to directly fit the empirical parameters of the potential to the key properties that determine whether or not the atomic level dynamics and most notably the phonon transport are described properly.
Editorial Summary
Molecular dynamics: Optimized potentials for studying phonons (分子动力学:针对声子研究优化的原子间相互作用势)
本研究开发了一个优化原子间相互作用势的计算框架,基于此可借助经典分子动力学方法更加精确地研究声子。分子动力学模拟是研究原子间相互作用不可或缺的工具。然而尽管该方法已得到广泛应用,但通常缺乏准确的原子间相互作用势参数来准确描述材料中声子的行为,因此难以阐释诸如热导率等相关材料性能。美国佐治亚理工学院的Asegun Henry教授领导了一个国际研究小组,提出了基于遗传算法和第一原理计算结果为输入,优化经验性原子间相互作用势的计算框架,由此可利用经典分子动力学模拟更精确地研究声子。该方法已经成功应用到硅、锗等半导体体系中,并有望延伸应用到合金和无序等系统中。
A framework has been developed that can optimize the potentials needed to more accurately study phonons using molecular dynamics. Molecular dynamics simulations are an indispensable tool for studying how atoms interact.Despite their widespread use, however, it is often difficult to determine the potentials needed to accurately describe the various interactions involved for phonons, which are the excitations that underpin physical properties such as thermal conductivity.An international team of researchers led by professor Asegun Henry from the Georgia Institute of Technology presents an approach, based on a genetic algorithm, that can optimise the empirical interatomic potentials for phonons from first principles inputs, that can be used in classical molecular dynamics simulations.And although they demonstrate this method with semiconducting silicon and germanium, it should be extendable to alloys and disordered systems.