A New Automated Preparation Process by Electrochemical Corrosion of STM Tungsten Tips

Scanning tunneling microscope (STM) is one of the most important instruments in the field of two-dimensional(2D) materials science while the STM tip is one of the most important parts in STM. Thus, we exhibit a new automated preparation process by electrochemical corrosion of STM tungsten(W) tips based on analog circuit technology in this paper. And the new preparation process is easy and reliable and can save time of researchers. Here, we will elaborate the preparation process and how the system works. In all, we will open up a new road in the field of preparation of STM tips.

Low temperature two STM tip tunneling measurements of a floating chemical potential Pb(111) surface

On a Pb(111) superconducting surface, low temperature dI/dV tunnelling spectra are recorded between two scanning tunnelling microscopes (STM) metallic tips with the Pb(111) sample metallic support non-grounded. The tunnelling current intensity I passing between the 2 tips through the sample is controlled by changing one or both STM vacuum tunnelling junction resistances. The chemical potential of this floating Pb(111) surface depends on the normalized ratio between those two quantum resistances. When ungrounded, the Pb(111) sample chemical potential balances between those of the 2 STM tips while tuning their respective tip end atomic apex to Pb(111) surface distances with a picometer precision without any physical contact between the STM tips and the surface.

Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips

Scanning tunneling microscopes (STM) are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.