Molecular dynamics studies of the dissociated screw dislocation in silicon.
Molecular dynamics studies of the dissociated screw dislocation in silicon.
复制标题
硅中解离螺旋位错的分子动力学研究。
DOI：
10.1088/0953-8984/22/7/074210
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Choudhury R
中科院分区：
文献类型：
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作者：
Choudhury R
表征共价、高佩尔斯势垒材料的位错运动是材料科学中的一个关键问题，尽管实验研究取得了进展，但对核心迁移中涉及的原子行为的实际观察仍然有限。我们采用了一种混合嵌入方案来研究在恒定外部应变的影响下，由两个30个部分组成的由层错带分开的硅中的解离螺旋位错。我们的“动态学习”混合技术允许我们使用紧密结合的Kwon势来计算核心区附近原子上的力，而体矩阵的其余部分则在经典近似内处理。对离解螺位错施加5%的应变，在600 K的温度下模拟100 ps的时间，我们观察到部分的运动通过两种不同的机制：双扭结形成和核心的方环扩散。我们的研究结果表明，在这些条件下，孤子或反相缺陷在种子结形成和随后的迁移中的作用是一个重要的因素，在未来的研究中应该考虑到这一点。
Characterizing the motion of dislocations through covalent, high Peierls barrier materials is a key problem in materials science, while despite the progress in experimental studies the actual observation of the atomistic behaviour involved in core migration remains limited. We have applied a hybrid embedding scheme to investigate the dissociated screw dislocation in silicon, consisting of two 30 partials separated by a stacking fault ribbon, under the influence of a constant external strain. Our'learn on the fly'hybrid technique allows us to calculate the forces on atoms in the vicinity of the core region using the tight binding Kwon potential, whilst the remainder of the bulk matrix is treated within a classical approximation. Applying a 5% strain to the dissociated screw dislocation, for a simulation time of 100 ps at a temperature of 600 K, we observe movement of the partials through two different mechanisms: double kink formation and square ring diffusion at the core. Our results suggest that in these conditions, the role of solitons or anti-phase defects in seeding kink formation and subsequent migration is an important one, which should be taken into account in future studies.