New measurements of nickelate superconductors reveal clues about their hidden digital conduct.
The mechanism behind high-temperature (TC) superconductivity stays considered one of condensed matter physics’ main unsolved issues. Chinese researchers have now made essential progress in finding out high-TC nickelate superconductors.
For the primary time, scientists recognized a nodeless superconducting hole and detected electron-boson coupling by analyzing the digital constructions of Ruddlesden-Popper bilayer nickelate superconducting skinny movies. The findings supply essential proof associated to 2 central questions in high-TC nickelates: “superconducting gap symmetry” and “superconducting pairing mechanism.”
The examine was led by Junfeng He of the University of Science and Technology of China (USTC), a part of the Chinese Academy of Sciences, in collaboration with groups led by Qikun Xue and Zhuoyu Chen of the Southern University of Science and Technology (SUSTech). It was revealed in Science on May 21, 2026.
Searching for the Superconducting Gap
Superconductivity, found in 1911, is thought for its uncommon electromagnetic properties and has change into a significant focus of physics analysis. Over the previous century, scientists have found copper-based and iron-based high-TC superconductors, however the mechanism behind high-TC superconductivity continues to be not totally understood. Nickel-based high-TC superconductors (nickelates) supply a brand new option to examine the issue.
In high-TC superconductors, “superconducting gap symmetry” is taken into account a key clue to how superconductivity works. One particularly essential query is whether or not the superconducting hole comprises “nodes” (factors the place the superconducting hole is zero) in momentum house. Using angle-resolved photoemission spectroscopy (ARPES), the workforce studied Ruddlesden-Popper bilayer nickelate superconducting skinny movies. They discovered no hole nodes anyplace in momentum house, a end result in keeping with s-wave (s±) superconducting hole symmetry.
Evidence of Electron-Boson Coupling
Another main query is how “electron pairs” type in high-TC superconductors. In idea, electrons can pair by “electron-boson coupling.” The researchers noticed a dispersion kink about 70 meV beneath the Fermi stage, which is a “finger print” of electron-boson coupling. This gives essential proof for understanding how electron pairing might happen.
In the collaboration, the SUSTech workforce led the skinny movie progress, whereas the USTC workforce carried out the digital construction measurements. To stop oxygen loss throughout pattern switch, the researchers developed a technique based mostly on liquid-nitrogen-cooled ultra-high vacuum low-temperature pattern quenching and switch. This strategy allowed samples to be moved efficiently from Shenzhen to Hefei and helped make the experiments attainable.
Reference: “Nodeless superconducting gap and electron-boson coupling in (La,Pr,Sm)3Ni2O7 films” by Jianchang Shen, Guangdi Zhou, Yu Miao, Peng Li, Zhipeng Ou, Yaqi Chen, Zechao Wang, Runqing Luan, Hongxu Sun, Zikun Feng, Xinru Yong, Yueying Li, Lizhi Xu, Wei Lv, Zihao Nie, Heng Wang, Haoliang Huang, Yu-Jie Sun, Qi-Kun Xue, Junfeng He and Zhuoyu Chen, 21 May 2026, Science.
DOI: 10.1126/science.adw8329
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.