Ab initio study of the surface properties and ideal strength of (100)silicon thin films
Ab initio study of the surface properties and ideal strength of (100)silicon thin films
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DOI：
10.1103/physrevb.72.165431
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发表时间：
2005-10
影响因子：
3.7
通讯作者：
Y. Umeno;Y. Umeno;A. Kushima;T. Kitamura;P. Gumbsch;Ju Li
中科院分区：
文献类型：
--
作者：
Y. Umeno;Y. Umeno;A. Kushima;T. Kitamura;P. Gumbsch;Ju Li
研究纳米结构材料的理想强度对于理解其力学性能具有重要意义。我们对具有（100）个表面的纳米级Si薄膜进行了从头开始建模，并计算了表面能和表面应力以及该结构的理想拉伸强度。薄膜的强度没有明显下降，厚度小于$1\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$。令人惊讶的是，表面重建也没有相当大的效果。这表明，在实验中发现的表面裂纹成核的较低应力是由于实质性缺陷造成的，而不是理想表面的内在影响。薄膜的带隙能量比体的带隙能量低，但在薄膜内高应变时仍有带隙存在。
Studying the ideal strength of nanostructured materials is important for understanding of their mechanical properties. We have performed ab initio modeling of nanoscale Si films with (100) surfaces and computed the surface energy and surface stress as well as the ideal tensile strength of the structure. The strength of the thin film is not significantly decreased down to a thickness of less than $1\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. Surprisingly, there is also no considerable effect of the surface reconstruction. This suggests that the lower stresses found for surface crack nucleation in an experiment are due to substantial flaws and not an intrinsic effect of the ideal surface. The band gap energy of the thin film is lower than that of the bulk, but a band gap remains up to high strain in the thin film.