Physicists develop new single-scanning scanning tunneling microscope with magnetic cooling to study quantum effects – sciencedaily
Scanning scopes capture images of materials with atomic precision and can be used to manipulate individual molecules or atoms. Researchers have used the instruments for many years to explore the world of nanoscopic phenomena. A new approach by physicists at Forschungszentrum Jülich now creates new possibilities for using devices to study quantum effects. Thanks to magnetic cooling, their tunneling microscope operates without any moving parts and is virtually vibration-free at extremely low temperatures as low as 30 millikelvins. The instrument can help researchers discover the exceptional properties of quantum materials, which are crucial for the development of quantum computers and sensors.
Physicists consider the temperature range near absolute zero to be a particularly exciting area of research. Thermal fluctuations are minimized. The laws of quantum physics come into play and reveal particular properties of materials. The electric current then flows freely without any resistance. Another example is a phenomenon called superfluidity: individual atoms merge into a collective state and move on top of each other without friction.
These extremely low temperatures are also necessary to research and exploit quantum effects for quantum computing. Researchers from all over the world as well as the Forschungszentrum Jülich are currently pursuing this goal at full speed. Quantum computers could be far superior to conventional supercomputers for certain tasks. However, development is still in its infancy. A major challenge is to find materials and processes that make possible complex architectures with stable quantum bits.
“I believe that a multipurpose microscope like ours is the tool of choice for this fascinating task, because it allows you to visualize and manipulate matter at the level of individual atoms and molecules in different ways,” explains Ruslan Temirov of the Forschungszentrum Jülich.
Over the years of work, he and his team have equipped a scanning tunneling microscope with magnetic cooling for this purpose. “Our new microscope differs from all others in the same way that an electric car differs from a vehicle with a combustion engine,” explains the physicist de Jülich. So far, researchers have relied on some kind of liquid fuel, a mixture of two isotopes of helium, to bring microscopes to such low temperatures. “During operation, this cooling mixture circulates continuously through thin pipes, resulting in increased background noise,” explains Temirov.
Jülich’s microscope cooling device, on the other hand, is based on the adiabatic demagnetization process. The principle is not new. It was used in the 1930s to reach for the first time temperatures below 1 kelvin in the laboratory. For the operation of microscopes, this has several advantages, explains Ruslan Temirov: “With this method, we can cool our new microscope simply by changing the strength of the electric current passing through an electromagnetic coil. Thus, our microscope has no moving parts. and is virtually vibration free. “
Scientists at Jülich are the first to build a scanning tunneling microscope using this technique. “The new cooling technology has several practical advantages. Not only does it improve the quality of the imaging, but the operation of the whole instrument and the whole setup is simplified, ”says Stefan Tautz, director of the institute. Thanks to its modular design, Jülich’s quantum microscope also remains open to technical advancements, he adds, as upgrades can be easily implemented.
“Adiabatic cooling is a real leap forward for tunneling microscopy. The advantages are so great that we are now developing a commercial prototype as the next step ”, explains Stefan Tautz. Quantum technologies are currently the subject of much research. The interest of many research groups for such an instrument is therefore assured.
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