Revolutionary microscopy: New procedure discovers hidden structures!

Revolutionary microscopy: New procedure discovers hidden structures!

A research team from University of Münster has developed innovative medical procedures for examining materials. Under the direction of Professor Dr. Anika Schlenhoff and Dr. Maciej Bazarnik tested an improved measuring method in scanning tunneling microscopy (RTM). The focus is on the structural and magnetic analysis of ultra-thin films, specifically a layer of magnetic iron hidden beneath a layer of graphene.

Conventional scanning tunneling microscopy is usually limited to the top atomic layer of a sample and uses electronic states located on the sample surface. The new procedure, however, removes this restriction. It allows researchers to look at conditions that exist in front of the surface and in the sample itself. This opens up new possibilities for studying electronic charge transfer at hidden interfaces.

Technological innovation through scanning tunneling microscopy

The scanning tunneling microscope contains a fine tip that is moved over the sample. When voltage is applied, a measurable tunneling current is created between the tip and the electrically conductive sample. This innovative technique, which is based on the quantum mechanical tunneling effect, makes it possible to create images of surfaces with the same density of electron states. The researchers report that the states lying in front of the surface penetrate into the sample and take on magnetic properties through interaction with the iron layer.

The spatial resolution of the new method allows a detailed analysis of the top layer and the underlying boundary layers. What is particularly notable is that it reveals differences in the vertical stacking sequence of the carbon atoms of graphene compared to the iron atoms. These specific differences could not have been decoded using conventional scanning tunneling microscopy, as the studies show.

The scanning tunneling microscope is used not only to analyze the local electronic structure, but also to perform scanning tunneling spectroscopy, which analyzes the energetic positions of the surface states. Wikipedia describes that tunneling currents are typically between 1 pA and 10 nA and depend on various parameters such as the work function of the electrons. In addition, techniques such as thermal, acoustic and mechanical isolation are required to stabilize the tip-sample distance.

The importance of research

The present study, published in the journal ACS Nano, could have far-reaching implications for materials science and nanotechnology. Armin B. and Heinrich Rohrer, the pioneers of this technology, have received recognition for their work on scanning tunneling microscopy since 1986 after winning the Nobel Prize in Physics. Their original development of the scanning tunneling microscope paved the way for numerous innovative applications.

Scanning tunneling microscopy has established itself as an indispensable tool in surface physics and chemistry. She provides deep insights into atomic processes and has helped illustrate quantum mechanics, including the creation and measurement of quantum corrals in the 1990s. These latest developments at the University of Münster could further push the boundaries of what has previously been possible in nanotechnology and open up new research approaches that go beyond current analytical methods.