Physicists have long known that electrons can form vortices from quantum materials. What's new is evidence that these small particles create tornado-like structures in momentum space.
In quantum materials called Tantalum harsenide (TAAS), electrons form vortices in momentum space. Image credits: Think-Design / Jochen Thamm.
Momentum space is a fundamental physics concept that explains electron motion in terms of energy and orientation rather than precise physical location.
The counterpart, the position space, is an area where familiar phenomena such as water vortices and hurricanes occur.
Until now, even quantum vortices of materials have been observed only in positional space.
Eight years ago, Dr. Roderrich Mossner of the Max Planck Institute for the Physics of Complex Systems and the Excellence ct.qmat of the Würzburg Denden cluster theorized that quantum tornadoes could also form in momentum spaces.
At the time, he described this phenomenon as a smoke ring. Because, like a ring of smoke, it is made up of vortices.
But up until now, no one knew how to measure them.
To detect quantum tornadoes in momentum space, Dr. Moessner and colleagues have enhanced a well-known technique called ARPES (angle-resolved light emission spectroscopy).
“ARPES is a fundamental tool in experimental solid-state physics,” explained Dr. Maximilian ünzelmann, researcher at the University of Werzburg, the experimental Physik VII and the Würzburg-Dresden Cluster of Excellence Cluster.
“It involves shining light on a material sample, extracting electrons, and measuring energy and outlet angles.”
“This allows us to see the electronic structure of the material directly in the momentum space.”
“By skillfully adapting this method, we were able to measure orbital angular momentum.”
Team's work It will be displayed in the journal Physics Review x.
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T. figgemeier et al. 2025. Imaging of orbital vortex lines in three-dimensional momentum space. Phys. Rev. X 15, 011032; doi:10.1103/physrevx.15.011032
Source: www.sci.news
