Wagner Philipp, Foster Adam, Yi Insook, Abe Masayuki, Sugimoto Yoshiaki, Hoffmann-Vogel Regina
Physikalisches Institut, Karlsruher Institut für Technologie, D-76128 Karlsruhe, Germany.
Department of Applied Physics, Aalto University School of Science, PO Box 11100, FI-00076 Aalto, Finland.
Nanotechnology. 2021 Jan 15;32(3):035706. doi: 10.1088/1361-6528/abbea8.
We have revealed processes of the tip apex distortion in the measurements of non-contact scanning force microscopy. High-spatial-resolution two-dimensional force mapping on KCl(100) surfaces for a large number of tips, seven tips, enabled us to see the complex behavior of the tip apex distortion. The tips are from Si without additional coating, but are altered by the tip-sample interaction and show the behavior of different atomic species. On the KCl(001) surfaces, the tip apex, consisting of K and Cl atoms or of Si, distorted several times while changing the distance even in a weak attractive region. There are variations in rigidity of the tip apex, but all tips distorted in the small attractive region. This complex behavior was categorized in patterns by our analyses. We compare the experimental force-distance data to atomistic simulations using rigid KCl-terminated tips and KCl-terminated tips with an additional KCl-pair designed to perform atomic jumps. We also compare the experimental force-distance data to first principles simulations using Si tips. We mainly find K-terminated tips and Si-terminated tips. We find that Si tips show only one force minimum whereas KCl-terminated tips show two force minima in line with the stronger rigidity of Si compared to KCl. At room temperature, the tip apex atoms can perform atomic jumps that change the atomic configuration of the tip apex.
我们在非接触式扫描力显微镜测量中揭示了针尖顶端畸变的过程。通过对大量（七个）针尖在KCl(100)表面进行高空间分辨率的二维力映射，我们得以观察到针尖顶端畸变的复杂行为。这些针尖由未额外涂层的硅制成，但会因针尖与样品的相互作用而发生改变，并呈现出不同原子种类的行为。在KCl(001)表面，由钾和氯原子或硅组成的针尖顶端，即使在弱吸引区域改变距离时也会多次畸变。针尖顶端的刚性存在变化，但所有针尖在小吸引区域都会畸变。通过我们的分析，这种复杂行为被归类为不同模式。我们将实验力-距离数据与使用刚性KCl终止针尖和设计用于进行原子跳跃的带有额外KCl对的KCl终止针尖的原子模拟进行比较。我们还将实验力-距离数据与使用硅针尖的第一性原理模拟进行比较。我们主要发现了钾终止针尖和硅终止针尖。我们发现，与KCl相比，硅针尖仅显示一个力最小值，而KCl终止针尖显示两个力最小值，这与硅更强的刚性一致。在室温下，针尖顶端原子可以进行原子跳跃，从而改变针尖顶端的原子构型。
