CO-tip manipulation using repulsive interactions
CO-tip manipulation using repulsive interactions
复制标题
使用排斥相互作用的 CO 尖端操纵
DOI：
10.1088/1361-6528/aae0df
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发表时间：
2018
期刊：
影响因子：
3.5
通讯作者：
and T K Yamada
中科院分区：
文献类型：
--
作者：
Nana K M Nazriq;E Minamitani;and T K Yamada
了解尖端与目标原子或分子之间的相互作用对于使用扫描隧道显微镜 (STM) 和原子力显微镜精确控制单个分子至关重要。在此，我们演示了使用 CO 功能化的 W 尖端以原子级精度操控 Cu (111) 基板上的目标 CO 分子。所有实验均在 5 K 的自制超高真空 STM 系统中进行。CO 尖端是通过从 Cu (111) 表面拾取单个 CO 分子来制造的。与金属尖端相反，CO 尖端和目标 CO 分子之间会发生排斥相互作用。这种排斥相互作用保证了完美的横向跳跃，而没有任何垂直跳跃。当同时测量的 I-z 曲线中电流突然下降时，直接监测跳变事件。从 I-z 曲线的斜率发现，CO 尖端和目标 CO 之间的势垒高度（∼ 9.5 eV）较大，这降低了尖端和样品之间的电子隧道概率。因此，电子驱动操纵不能成为CO-CO排斥操纵的主要触发因素。 CO 尖端只能操纵目标 CO 分子，即使另一个 CO 分子位于约 0.5 nm 之外。统计测量表明，顶部位置最近的邻居是跳跃后能量稳定的位置。然而，如果CO目标在邻近位置有另一个CO分子（表示为“对”），则目标CO跳跃的距离将超过两倍。这意味着 CO 尖端经历了来自该对的更大的排斥相互作用。这些对 CO 尖端操作的观察对于二维人工分子网络的设计以及更好地理解催化氧化过程很有用。
Understanding the interactions between a tip apex and a target atom or molecule is crucial for the manipulation of individual molecules with precise control by using scanning tunnelling microscopy (STM) and atomic force microscopy. Herein, we demonstrate the manipulation of target CO molecules on a Cu (111) substrate using a CO-functionalized W tip with atomic-scale accuracy. All experiments were performed in a home-built ultra-high vacuum STM system at 5 K. The CO-tip was fabricated by picking up a single CO molecule from a Cu (111) surface. In contrast to a metal tip, repulsive interactions occur between the CO-tip and the target CO molecule. This repulsive interaction promises perfect lateral hopping without any vertical hopping. Hopping events were directly monitored as sudden current drops in the simultaneously measured I–z curves. A larger barrier height between the CO-tip and the target CO (∼ 9.5 eV) was found from the slope of the I–z curve, which decreases the electron tunnelling probability between the tip and sample. Therefore, electron-driven manipulation cannot be a major trigger for the CO–CO repulsive manipulation. The CO-tip is able to manipulate only the target CO molecule, even when another CO molecule was located∼ 0.5 nm away. Statistical measurements revealed that the nearest neighbour atop site is the energetically stable position after hopping. However, if the CO target has another CO molecule in a neighbouring position (denoted as a'pair'), the target CO hops more than twice as far. This means that the CO-tip experiences a larger repulsive interaction from the pair. These observations of CO-tip manipulation are useful for the design of two-dimensional artificial molecular networks as well as for developing a better understanding of catalytic oxidation processes.