A nodeless superconducting gap has been identified in Ruddlesden-Popper bilayer nickelate thin films, consistent with s-wave (s±) symmetry.
A dispersion kink observed 70 meV below the Fermi level suggests electron-boson coupling as a potential mechanism for electron pairing.
Background
High-temperature superconductivity remains an unsolved problem in condensed matter physics. Nickel-based high-TC superconductors (nickelates) provide a new platform for investigation, offering fresh opportunities to unravel the mechanisms behind unconventional superconductivity.
Method
The study combined thin film growth by a team at Southern University of Science and Technology (SUSTech) with electronic structure measurements using angle-resolved photoemission spectroscopy (ARPES) by a team at University of Science and Technology of China (USTC). A key technical innovation was the development of a liquid-nitrogen-cooled ultra-high vacuum low-temperature sample quenching and transfer method. This was critical to prevent oxygen loss during sample transport between Shenzhen and Hefei.
Publication
The research was led by Junfeng He (USTC) in collaboration with Qikun Xue and Zhuoyu Chen (SUSTech) and published in Science on May 21, 2026 (DOI: 10.1126/science.adw8329).