Scientists from the University of California, Irvine (UCI) have made a breakthrough in understanding how superconductivity works in an iron-based material.
Their findings, published in Nature, reveal how tiny atomic vibrations can boost superconductivity, opening doors to exciting technological advancements.
The team studied iron selenide (FeSe), a special material known for its ability to conduct electricity without resistance at very low temperatures.
To enhance its properties, they layered FeSe as an ultrathin film on a strontium titanate (STO) substrate.
By using advanced spectroscopy tools at UCI’s Materials Research Institute, they were able to see atomic vibrations in stunning detail.
These vibrations created what scientists call “phonons”—tiny particles that carry thermal energy.
The researchers discovered that phonons at the interface between FeSe and STO play a key role in superconductivity.
Specifically, oxygen atoms in the STO layer vibrate in a way that interacts strongly with electrons in the FeSe layer.
This interaction, called electron-phonon coupling, helps FeSe transition to a superconducting state at much higher temperatures than usual.
“By carefully studying the overlap between electron and phonon wave functions, we saw how this interaction boosts the superconducting temperature,” said Xiaoqing Pan, lead author of the study and a distinguished professor at UCI.
The FeSe film showed a superconducting transition at 65 Kelvin (about -340°F)—the highest temperature observed for a material of this kind.
Importantly, the researchers noticed that the more uniform the interface between the FeSe and STO layers, the better the material performed.
“Our instruments allowed us to image the vibrations and measure how the spacing between layers affected the superconducting gap,” Pan explained. “We found that uniform spacing leads to stronger electron-phonon coupling and higher superconducting temperatures.”
Ruqian Wu, a physics professor at UCI and co-author of the study, highlighted the value of combining experimental data with theoretical simulations.
“By working together, we could identify how individual atoms contribute to superconductivity. This deepens our understanding and helps us design better materials.”
This discovery is a big step toward using superconductors in practical applications.
Superconductors have the potential to revolutionize technology by enabling more efficient quantum computers, faster transportation with magnetic levitation, and advanced medical equipment for diagnosis and treatment.
With these findings, the researchers hope to make superconductors more scalable and accessible for future innovations. “This work brings us closer to unlocking the full potential of superconducting materials,” Pan said.
Source: UC Irvine.
