Researchers have discovered a unique phenomenon in a special type of metal called Kagome metal, named after a traditional Japanese basket-weaving pattern.
This metal’s atomic structure looks like interlaced triangles, similar to the Kagome design.
Since their discovery in 2019, scientists have been eager to understand the properties and potential uses of Kagome metals.
A new study by Florida State University Assistant Professor Guangxin Ni and his team has found that a particular Kagome metal, cesium vanadium antimonide (CsV3Sb5), can interact with light to create special waves called plasmon polaritons.
These waves are made up of linked electrons and electromagnetic fields and usually form when light or other electromagnetic waves hit a material.
The study was published in Nature Communications.
While previous research has studied plasmons in regular metals, Kagome metals present more complex behaviors. In this study, researchers focused on CsV3Sb5 to understand its unique properties better.
They discovered plasmons in this metal for the first time and found that their wavelength changes with the metal’s thickness.
Moreover, changing the frequency of a laser shining on the metal caused the plasmons to transform into “hyperbolic bulk plasmons,” which move through the material instead of staying on the surface.
These new waves lose less energy, allowing them to travel more effectively.
“Hyperbolic plasmon polaritons are rare in natural metals, but our research shows how electron interactions can create these unique waves at the nanoscale,” Ni explained. “This breakthrough is crucial for advancing technologies in nano-optics and nano-photonics.”
To study how plasmons interacted with CsV3Sb5, the researchers grew single crystals of the metal and placed thin flakes on specially prepared gold surfaces. Using lasers and scanning infrared nano-imaging, they observed how the metal’s plasmon polaritons changed in response to different conditions.
“CsV3Sb5 is fascinating because of how it interacts with light on a very small scale, known as nano-optics,” said lead author Hossein Shiravi, a graduate research assistant at the FSU National High Magnetic Field Laboratory.
“We found that over a wide range of infrared light frequencies, the electrical properties within the metal triggered the formation of hyperbolic bulk plasmons.”
These hyperbolic patterns mean less energy loss. The findings provide new insights into how CsV3Sb5 behaves, offering potential real-world applications. Hyperbolic plasmon polaritons could enhance optical communication systems, enable super-clear imaging, and improve photonic devices.
They might also be useful in sensing environmental changes and medical diagnostics because they respond strongly to their surroundings.
“This exciting breakthrough shows that unconventional metals like CsV3Sb5 have the potential to revolutionize future technologies,” Ni said. The team’s work highlights the importance of continuing to explore nano-optical phenomena in these unique materials.
