Physics: Current generated by the quantum Hall effect has additional magnetic properties

Electricity flows through all types of electronic devices, whether it’s a cell phone or a computer. However, this generates heat, which means energy is lost. This also means that traditional computer chips cannot be infinitely shrunk. In the field of spin-orbit electronics, researchers are looking for alternatives for storing and processing information without losing energy. The basic concept is to use not only the electron’s charge but also its spin and orbital moment when processing information. Spin is the intrinsic angular momentum of the electron, and the orbital moment is generated by the electron’s motion around the nucleus. “Combining these two effects will allow us to design new devices that are more powerful and more efficient,” said Professor Ingrid Mertig, a physicist at the University of Michigan.

The basis of this new research is the quantum Hall effect. Klaus von Klitzing won the 1985 Nobel Prize in Physics for his discovery. This effect is observed when electrons are subjected to very strong magnetic fields at very low temperatures. “The quantum Hall effect is special because the current generated flows only at the edges of the sample. Furthermore, the associated resistance can only assume specific values,” explains Dr. Börge Göbel. Although scientists have been aware of this effect for decades, the team’s calculations provide new insights: edge currents are also magnetic due to the electrons’ orbital moments. “In the future, they can be used to transmit more information and operate electrical equipment more efficiently,” Goebel said. Notably, this new effect arises outside the quantum Hall effect and, unlike what is often the case in spintronics, is not associated with rare and expensive materials.

Goebel and Meltig are already continuing their research as part of the international research project Obelix, funded by the European Innovation Council’s Pathfinder programme. The goal is to find new, marketable technologies. To this end, Mertig and Göbel are collaborating with research institutions in Germany, France and Sweden.

Mertig and Göbel are also contributing their expertise in the field of spin-orbit electronics through participation in the planned “Centre for Chiral Electronics” to which MLU is applying for strategic excellence funding together with Freie Universität Berlin and the University of Regensburg. The Max Planck Institute for Microstructural Physics in Halle is also involved.