Force Field Analysis Suggests a Lowering of Diffusion Barriers in Atomic Manipulation Due to Presence of STM Tip
Force Field Analysis Suggests a Lowering of Diffusion Barriers in Atomic Manipulation Due to Presence of STM Tip
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DOI：
10.1103/physrevlett.114.146101
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发表时间：
2015-04-06
影响因子：
8.6
通讯作者：
Giessibl, Franz J.
中科院分区：
文献类型：
--
作者：
Emmrich, Matthias;Schneiderbauer, Maximilian;Giessibl, Franz J.
我们通过在液氦温度下结合扫描隧道显微镜和原子力显微镜研究了 Cu(111) 表面上 CO 原子操纵的物理过程。在原子操纵中，利用吸附物与基底和尖端的相互作用将吸附的原子或分子排列在表面上。虽然之前的实验与尖端和基底力的线性叠加模型一致，但我们发现力阈值取决于尖端的力场。在这里，我们使用一氧化碳前原子识别（COFI）来表征尖端的力场。显示具有吸引中心的 COFI 轮廓的尖端可以在任何方向上操纵 CO，而具有排斥中心的尖端只能在某些方向上操纵。力阈值在 1 至 10 mV 范围内与偏置电压无关，在 4.5 至 7.5 K 范围内与温度无关。
We study the physics of atomic manipulation of CO on a Cu(111) surface by combined scanning tunneling microscopy and atomic force microscopy at liquid helium temperatures. In atomic manipulation, an adsorbed atom or molecule is arranged on the surface using the interaction of the adsorbate with substrate and tip. While previous experiments are consistent with a linear superposition model of tip and substrate forces, we find that the force threshold depends on the force field of the tip. Here, we use carbon monoxide front atom identification (COFI) to characterize the tip's force field. Tips that show COFI profiles with an attractive center can manipulate CO in any direction while tips with a repulsive center can only manipulate in certain directions. The force thresholds are independent of bias voltage in a range from 1 to 10 mV and independent of temperature in a range of 4.5 to 7.5 K.