Atomic theory of scanning tunneling microscopy.
Atomic theory of scanning tunneling microscopy.
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扫描隧道显微镜的原子理论。
DOI：
10.1103/physrevb.40.10286
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Ciraci
中科院分区：
文献类型：
--
作者：
Tekman;Ciraci
我们提出了一种定量分析扫描-隧道显微镜图像的修改，由于在接近样品表面的尖端引起的电子态的局部扰动。利用经验紧密结合方法，我们计算了由单原子尖端和石墨表面组成的原型尖端-样品系统的电子态与尖端-样品距离的函数关系。我们发现，当尖端接近样品时，它们的状态开始相互作用，并在小尖端-样品分离时横向限制在尖端附近。这些状态通过电子连接针尖和样品表面来影响隧道现象。讨论了尖端诱导局域态的影响，并通过引入尖端诱导态，重新建立了隧道电流的表达式。利用该表达式计算表明，扫描隧道显微镜得到的波纹振幅被增强，偏离了与裸露样品在尖端中心处的费米能级的局部态密度的比例。
We present a quantitative analysis of the modifications of the scanning-tunneling-microscopy images due to the local perturbations of the electronic states induced by the tip in close proximity to the sample surface. Using an empirical tight-binding method, we have calculated the electronic states of a prototype tip-sample system consisting of a single-atom tip and the graphite surface, as a function of the tip-sample distance. We find that as the tip approaches the sample, their states start to interact and become laterally confined in the vicinity of the tip at small tip-sample separation. These states influence the tunneling phenomenon by connecting the tip and sample surface electronically. The effect of the tip-induced localized states is discussed, and the expression for the tunneling current is reformulated by incorporating the tip-induced states. Calculations using this expression show that the corrugation amplitude obtained from scanning tunneling microscopy is enhanced and deviates from the proportionality to the local density of states of the bare sample at the Fermi level evaluated at the center of the tip.