Simulations of laser-induced dynamics in free-standing thin silicon films
Simulations of laser-induced dynamics in free-standing thin silicon films
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DOI：
10.1007/s00339-017-1230-9
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发表时间：
2017-09
期刊：
影响因子：
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通讯作者：
T. Zier;E. S. Zijlstra;S. Krylow;Martin E. Garcia
中科院分区：
文献类型：
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作者：
T. Zier;E. S. Zijlstra;S. Krylow;Martin E. Garcia
飞秒激光脉冲可以在材料中引起巨大的结构变化。在大多数情况下，这些变化伴随着材料表面的结构重建。到目前为止，由于技术问题，从头算方法还不能模拟具有开放边界条件的激光激发材料，如薄膜。我们已经成功地克服了这些问题，并在进行分子动力学模拟的激光激发硅薄膜。这一新阶段的从头算分子动力学模拟将在实验和理论上对激光激发固体领域产生广泛的影响，可以解决以前无法解决的问题。我们的研究结果表明，对于一个中等的激发强度呼吸模式诱导在整个膜在垂直于表面的方向。在高强度制度，我们预测的时间演化的实验可访问的结构因子强度依赖于进入表面的深度。结果表明，表面比薄膜中心对飞秒激光的激发有更大的弹性。
Femtosecond-laser pulses can induce tremendous structural changes in materials. In most cases these changes are accompanied by a structural reconstruction of the materials’ surface. So far, ab initio methods were not able to simulate laser-excited materials with open boundary conditions, like, films due to technical problems. We have succeeded in overcoming these problems and in performing molecular dynamics simulations of laser-excited thin silicon films. This new stage of ab initio molecular dynamics simulations will influence widely the field of laser-excited solids in both, experiment and theory, allowing to address questions that were unreachable before. Our results indicate that for a moderate excitation strength a breathing mode is induced in the whole film in the direction perpendicular to the surface. In the high intensity regime we predict the time-evolution of experimentally accessible structure factor intensities dependent on the depth into the surface. The results indicate that the surfaces are more resilient than the film center to the femtosecond-laser excitation.