Assessment of Scanning Tunneling Spectroscopy Modes Inspecting Electron Confinement in Surface-Confined Supramolecular Networks
Assessment of Scanning Tunneling Spectroscopy Modes Inspecting Electron Confinement in Surface-Confined Supramolecular Networks
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DOI：
10.1038/srep01454
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发表时间：
2013-03-18
影响因子：
4.6
通讯作者：
Barth, Johannes V.
中科院分区：
文献类型：
--
作者：
Krenner, Wolfgang;Kuehne, Dirk;Barth, Johannes V.
扫描隧道光谱（STS）通过测量与表面态密度（DOS）近似成比例的微分电导（dI/dV），实现了对样品表面态密度（DOS）的局部能量分辨研究。通过在恒定电流条件下获得dI/dV图来检查元素样品的电子结构是流行的。在这里，我们展示了复杂的STS映射的样品表现出强烈的电子密度和局部功函数的变化。研究了多孔有机网络对Ag（111）表面态的限制，得到了恒流（CC）和开环反馈（OFL）条件下的图。我们展示了CC地图如何明显偏离物理上更有意义的OFL地图。通过对OFL数据应用重整化过程，我们可以模拟CC模式的伪效应，从而使引起CC图中伪影的物理效应合理化。
Scanning tunneling spectroscopy (STS) enables the local, energy-resolved investigation of a samples surface density of states (DOS) by measuring the differential conductance (dI/dV) being approximately proportional to the DOS. It is popular to examine the electronic structure of elementary samples by acquiring dI/dV maps under constant current conditions. Here we demonstrate the intricacy of STS mapping of samples exhibiting a strong corrugation originating from electronic density and local work function changes. The confinement of the Ag(111) surface state by a porous organic network is studied with maps obtained under constant-current (CC) as well as open-feedback-loop (OFL) conditions. We show how the CC maps deviate markedly from the physically more meaningful OFL maps. By applying a renormalization procedure to the OFL data we can mimic the spurious effects of the CC mode and thereby rationalize the physical effects evoking the artefacts in the CC maps.