Visualization of dislocation dynamics in colloidal crystals
Visualization of dislocation dynamics in colloidal crystals
复制标题
DOI：
10.1126/science.1102186
复制
发表时间：
2004-09-24
期刊：
影响因子：
56.9
通讯作者：
Spaepen, F
中科院分区：
文献类型：
--
作者：
Schall, P;Cohen, I;Spaepen, F
在原子晶体中产生大的不可逆应变的主要机制是位错的运动，位错是晶格中的一类线缺陷。在这里，我们发现在应变胶体晶体中也可以观察到位错的运动，从而可以详细地研究它们的拓扑结构和传播。描述了一种激光衍射显微镜装置，用于研究胶体晶体薄膜中失配位错的生长和结构。利用激光扫描共聚焦显微镜获得了单粒子水平上的互补性微观信息。这两种技术的结合使我们能够在一系列长度尺度上研究位错，使我们能够确定失配位错的重要参数，如临界薄膜厚度、位错密度、Burgers矢量和位错运动的晶格阻力。我们将观察到的位错确定为束缚了能量消失的堆积层错的Shockley分项。值得注意的是，我们发现，即使在几个晶格矢量的尺度上，位错行为也可以用通常用来描述原子晶体中位错的连续统方法来很好地描述。
The dominant mechanism for creating large irreversible strain in atomic crystals is the motion of dislocations, a class of line defects in the crystalline lattice. Here we show that the motion of dislocations can also be observed in strained colloidal crystals, allowing detailed investigation of their topology and propagation. We describe a laser diffraction microscopy setup used to study the growth and structure of misfit dislocations in colloidal crystalline films. Complementary microscopic information at the single-particle level is obtained with a laser scanning confocal microscope. The combination of these two techniques enables us to study dislocations over a range of length scales, allowing us to determine important parameters of misfit dislocations such as critical film thickness, dislocation density, Burgers vector, and lattice resistance to dislocation motion. We identify the observed dislocations as Shockley partials that bound stacking faults of vanishing energy. Remarkably, we find that even on the scale of a few lattice vectors, the dislocation behavior is well described by the continuum approach commonly used to describe dislocations in atomic crystals.