A Chinese research team has made significant progress in understanding high-temperature superconductivity, providing crucial experimental evidence that offers new insights into its underlying mechanisms.
Research conducted by researchers from the University of Science and Technology of China ( USTC) and Southern University of Science and Technology (SUSTech) has successfully observed a "nodeless superconducting gap" and "electron -boson coupling " in a nickel oxide-based high-temperature superconducting thin film for the first time.
The findings were recently published online in the journal Science .
According to Xue Qikun, an academician at the Chinese Academy of Sciences (CAS) and a professor at SUSTech, the symmetry of the superconducting gap and the mechanism of superconducting pairing are two key issues in high-temperature superconductivity research.
This symmetry determines whether the superconducting gap is uniform. In superconductors, electrons must pair up to conserve energy, a process measured by the "superconducting gap."
While conventional superconductors have a completely uniform gap with no “nodes” (points where the gap is zero), copper-based superconductors are thought to have nodes in certain directions.
By studying the new nickel-based film, the research team discovered that its superconducting gap lacks nodes. This suggests that nickel-based and copper-based superconductors may operate under different rules of physics.
The research team also discovered how electrons can pair up. Because electrons naturally repel each other, they typically require a "middleman" to hold them together.
The researchers found a unique “fingerprint” signal in the energy data, suggesting that the intermediate boson may act as a bridge in facilitating assembly in nickel-based materials.
Nickel-based superconductivity research is currently one of the leading topics in the global scientific community, characterized by extreme technical challenges in material preparation and equipment development.
Prior to this discovery, the team had made a series of systematic advances in materials synthesis and electronic structure studies, including the development of atomic-level preparation techniques for complex oxides, which paved the way for this research.
"This is a significant step in quantum materials research," Xue said. "It reflects China's deepening role in cutting-edge physics and its growing contribution to the global effort to understand high-temperature superconductivity."
