Stasevich T J, Tao Chenggang, Cullen William G, Williams Ellen D, Einstein T L
Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA.
Phys Rev Lett. 2009 Feb 27;102(8):085501. doi: 10.1103/PhysRevLett.102.085501.
The decoration of hexagonal Ag/Ag(111) monolayer islands by chains of C60, observed via STM at 300 K, dramatically changes the nanocrystalline shape and fluctuations of the islands. We tune coverage so that a single chain of C60 fully decorates each Ag island boundary, forming a closed circular "necklace." We model the C60-induced rounding in terms of competing energetic and entropic effects. We thereby characterize the decorated-step fluctuations and estimate the C60-Ag and C60-C60 attractions to be approximately 0.13 and approximately 0.03 eV, respectively. Generalizations of our model show that decorating molecules of both circular and rectangular surface-projected symmetry will similarly lower the energy of fully kinked boundaries, leading to corner rounding and reorientations by 30 degrees on (111) surfaces and 45 degrees on (100) surfaces.
通过在300 K下的扫描隧道显微镜（STM）观察到，C60链对六边形Ag/Ag(111)单层岛的修饰显著改变了岛的纳米晶体形状和起伏。我们调整覆盖率，使单链C60完全修饰每个Ag岛边界，形成一个封闭的圆形“项链”。我们根据相互竞争的能量和熵效应，对C60诱导的圆角进行建模。由此，我们表征了修饰台阶的起伏，并估计C60与Ag以及C60与C60之间的吸引力分别约为0.13 eV和约0.03 eV。我们模型的推广表明，具有圆形和矩形表面投影对称性的修饰分子同样会降低完全扭折边界的能量，导致在(111)表面上的角变圆以及重新取向30度，在(100)表面上重新取向45度。
