Abstract Considering studies of molecular adsorption we review recent developments in the field of scanning probe microscopy and in particular in scanning tunnelling microscopy, concentrating on the progress that has been achieved by controlled decoration of the microscope tip. A view is presented according to which the tip decoration generally introduces additional degrees of freedom into the scanning junction and thus extends its functionality. In particular tips decorated with atomic point-like particles may attain the additional function of a force sensor which is realized through the degrees of freedom associated with the relative position of the decorating probe-particle with respect to the tip. It is shown how the force sensor function of such tips helps when studying large molecular adsorbates. Further prospects of more complex junctions equipped with numerous internal degrees of freedom are discussed. It is argued that the main problem impeding the utilization of such junctions is related to their control. An approach towards a higher degree of control is presented that is based on the analysis of single molecule manipulation experiments.

中文翻译：

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具有额外自由度的隧道结：扫描探针显微镜的扩展工具箱

摘要 考虑到分子吸附的研究，我们回顾了扫描探针显微镜领域的最新发展，特别是扫描隧道显微镜，重点关注显微镜尖端受控装饰所取得的进展。根据该视图，尖端装饰通常将额外的自由度引入扫描结，从而扩展其功能。特别地，用原子点状粒子装饰的尖端可以获得力传感器的附加功能，其通过与装饰探针粒子相对于尖端的相对位置相关联的自由度来实现。显示了在研究大分子吸附物时，此类尖端的力传感器功能如何提供帮助。讨论了配备多个内部自由度的更复杂连接的进一步前景。有人认为，阻碍利用这些连接点的主要问题与它们的控制有关。提出了一种基于单分子操作实验分析的更高程度控制的方法。