arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1012.0238cond-mat.softcond-mat.dis-nn
收藏

椭球粒子玻璃中的转动和平移声子模

Rotational and Translational Phonon Modes in Glasses Composed of Ellipsoidal Particles

Peter J. Yunker, Ke Chen, Zexin Zhang, Wouter G. Ellenbroek, Andrea J. Liu, A. G. Yodh

摘要:

实验研究了颗粒形状对胶体玻璃振动特性的影响。“椭球玻璃”是通过将聚苯乙烯球拉伸到不同的纵横比,然后将所得的椭球颗粒以高填充分数悬浮在水中而产生的。通过测量粒子之间的位移相关性,我们提取相应的“影子”椭球玻璃的振动特性与相同的几何配置和相互作用的“源”悬浮液,但没有阻尼。长/短轴纵横比为$\sim$ 1.1的椭球粒子组成的玻璃中的低频模式被观察到具有主要的旋转特征。相比之下,具有较大纵横比的椭球颗粒玻璃($\sim$ 3.0)中的低频模式表现出旋转和平移特性的混合。所有玻璃样品的特征在于具有不同纵横比的颗粒的分布。有趣的是,即使在相同的样品中,也发现小纵横比颗粒相对更多地参与旋转模式,而大纵横比颗粒倾向于相对更多地参与平移模式。

英文摘要:

The effects of particle shape on the vibrational properties of colloidal glasses are studied experimentally. 'Ellipsoidal glasses' are created by stretching polystyrene spheres to different aspect ratios and then suspending the resulting ellipsoidal particles in water at high packing fraction. By measuring displacement correlations between particles, we extract vibrational properties of the corresponding "shadow" ellipsoidal glass with the same geometric configuration and interactions as the 'source' suspension but without damping. Low frequency modes in glasses composed of ellipsoidal particles with major/minor axis aspect ratios $\sim$1.1 are observed to have predominantly rotational character. By contrast, low frequency modes in glasses of ellipsoidal particles with larger aspect ratios ($\sim$3.0) exhibit a mix of rotational and translational character. All glass samples were characterized by a distribution of particles with different aspect ratios. Interestingly, even within the same sample it was found that small-aspect-ratio particles participate relatively more in rotational modes, while large-aspect-ratio particles tend to participate relatively more in translational modes.

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。

↑