Reviewed by Lexie CornerApr 23 2025
A research team at the University of Stuttgart has explored the interaction between light and a metal surface, leading to the discovery of new behaviors. “Our results add another chapter to the emerging field of skyrmion research,” said Professor Harald Giessen, Head of the Fourth Physics Institute at the University of Stuttgart. The team demonstrated the formation of "skyrmion bags" of light on a metal surface.
Skyrmion bags: Physicists at the University of Stuttgart have discovered these vortex-like structures on a metal surface for the first time. Image Credit: University of Stuttgart / Patrick Walter
A Better Understanding of Physical Phenomena
Skyrmions, a mathematical concept used to describe vortex-like structures, offer researchers a better understanding of fundamental physical relationships. This theoretical concept has been experimentally confirmed in various fields, including magnetic solids and material surfaces.
Giessen's team explored whether light impinging on the structured surface of a thin gold layer could behave as skyrmion bags that follow specific symmetries.
These skyrmion bags consist of smaller skyrmions contained within a larger skyrmion. The researchers created intricate grooves on the gold surface using two twisted hexagons in their experiment, with each hexagon generating a skyrmion light field.
Targeted Manipulation of Light Fields
We then observed a superposition of two skyrmion light fields, from which the skyrmion bags formed.
Julian Schwab, Study Lead Author and Doctoral Student, University of Stuttgart
By adjusting the degree of twisting between the light fields, the researchers could control the number of skyrmions within the skyrmion bags.
In other words, the researchers could precisely control light fields and shape them in ways that would not typically occur. Giessen’s team collaborated with researchers at the University of Duisburg-Essen for experimental verification and with the Technion in Haifa for the theoretical understanding of the phenomenon.
Fundamental Research with Application Potential
This remains basic physics for now. However, the unique properties of these light-field skyrmions have generated interest in potential technical applications. It is yet to be determined whether the gold surface developed by Giessen's team will be suitable for such applications.
“If someone finds a suitable material, our concept could be applied in microscopy,” stated Giessen.
With specialized microscopes, it is possible to achieve resolutions that would otherwise be unattainable due to the limitations imposed by the wavelength of light.
Journal Reference:
Schwab, J., et al. (2025). Skyrmion bags of light in plasmonic moiré superlattices. Nature Physics. doi.org/10.1038/s41567-025-02873-1.