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arXiv 1109.0107cond-mat.soft
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过冷液体结晶的微观途径

The microscopic pathway to crystallization in supercooled liquids

John Russo, Hajime Tanaka

摘要:

尽管结晶过程具有基础性和技术性的重要性,但对结晶过程的微观理解仍然难以捉摸。通过硬球模型的计算机模拟,我们揭示了热涨落驱动从过冷液体态到晶态转变的机制。特别是,我们发现,在键取向顺序的波动触发成核过程中,相反的共同信念,即过渡是由密度波动。此外,键取向波动的分析表明,这些不仅充当成核过程的晶种,而且i)确定由它们成核的特定多晶型物,和ii)在高密度下有利于形成五重结构,这可以阻碍晶体的形成。这些结果对我们理解玻璃化与结晶化之间的关系具有重要意义。

英文摘要:

Despite its fundamental and technological importance, a microscopic understanding of the crystallization process is still elusive. By computer simulations of the hard-sphere model we reveal the mechanism by which thermal fluctuations drive the transition from the supercooled liquid state to the crystal state. In particular we show that fluctuations in bond orientational order trigger the nucleation process, contrary to the common belief that the transition is initiated by density fluctuations. Moreover, the analysis of bond orientational fluctuations shows that these not only act as seeds of the nucleation process, but also i) determine the particular polymorph which is to be nucleated from them and ii) at high density favour the formation of fivefold structures which can frustrate the formation of crystals. These results can shed new light on our understanding of the relationship between crystallization and vitrification.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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