Physics of Interfaces and Nanomaterials, MESA^{+} Institute for Nanotechnology, University of Twente, P. O. Box 217, NL-7500 AE Enschede, The Netherlands.
Phys Rev Lett. 2013 Feb 15;110(7):076101. doi: 10.1103/PhysRevLett.110.076101.
We have used low energy electron microscopy to demonstrate how the interaction of 4,4'-biphenyldicarboxylic acid (BDA) molecules with (steps on) the Cu(001) surface determines the structure of supramolecular BDA networks on a mesoscopic length scale. Our in situ real time observations reveal that steps are permeable to individual molecules but that the change in crystal registry between different layers of the Cu substrate causes them to be completely impermeable to condensed BDA domains. The resulting growth instabilities determine the evolution of the domain shape and include a novel Mullins-Sekerka-type growth instability that is characterized by high growth rates along, instead of perpendicular to, the Cu steps. This growth instability is responsible for the majority of residual defects in the BDA networks.
我们使用低能电子显微镜证明了 4,4'-联苯二甲酸（BDA）分子与（台阶上的）Cu(001)表面的相互作用如何决定了超分子 BDA 网络在介观长度尺度上的结构。我们的原位实时观察表明，台阶允许单个分子通过，但 Cu 衬底不同层之间的晶体注册变化导致它们对凝聚的 BDA 域完全不可渗透。由此产生的生长不稳定性决定了畴形状的演化，包括一种新的 Mullins-Sekerka 型生长不稳定性，其特征是沿 Cu 台阶而不是垂直于 Cu 台阶的高生长速率。这种生长不稳定性是 BDA 网络中大多数残余缺陷的原因。
