Physik Department E20, Technische Universität München, James-Franck Straße, 85748 Garching, Germany.
Sci Rep. 2013;3:1454. doi: 10.1038/srep01454.
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.
扫描隧道谱（STS）通过测量与态密度（DOS）大致成正比的微分电导（dI/dV），实现了对样品表面 DOS 的局部、能量分辨的研究。通过在恒流条件下获取 dI/dV 图谱来研究基本样品的电子结构是很常见的。在这里，我们展示了在具有源自电子密度和局部功函数变化的强波纹的样品的 STS 映射的复杂性。通过恒流（CC）和开环反馈（OFL）条件下获得的图谱，研究了多孔有机网络对 Ag(111) 表面态的限制。我们展示了 CC 图谱如何与物理上更有意义的 OFL 图谱明显偏离。通过对 OFL 数据应用重整化程序，我们可以模拟 CC 模式的虚假效应，从而合理化在 CC 图谱中产生伪影的物理效应。
