Since the discovery of superconductivity, searching for materials with higher transition temperatures ( T c ) has remained a core objective of condensed matter physics. From early elemental metals to cuprate and iron-based superconductors, every leap in T c has propelled scientific development and expanded application prospects. Recently, nickelates have emerged as the third class of high-temperature superconducting systems, garnering significant attention. While the superconducting onset transition temperature ( T c onset ) of pressurized nickelate bulks has reached 80 K or even 96 K , the T c onset of ambient-pressure nickelate films has been previously limited to approximately 40-50 K.
Recently, a breakthrough in ambient-pressure nickelate superconductivity was achieved by the research team led by Qi-Kun Xue and Zhuoyu Chen from the State Key Laboratory of Quantum Functional Materials, the Department of Physics at Southern University of Science and Technology (SUSTech), and the Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area. This study utilized the team’s self-developed “Gigantic-oxidative Atomic-layer-by-layer Epitaxy” (GAE) method. By creating extreme non-equilibrium growth conditions, the team effectively resolved the thermodynamic conflict between structural stability and the high oxidation state required for the nickelate superconducting phase. High-quality epitaxial (La,Pr) 3 Ni 2 O 7 thin films were grown on SrLaAlO 4 substrates, reaching a record T c onset of 63 K and a zero-resistance temperature ( T c zero ) of 37 K. Furthermore, the Meissner effect, representing global phase coherence, was significantly enhanced compared to previous records. These findings were published in National Science Review under the title “Superconductivity onset above 60 K in ambient-pressure nickelate films”.
The research revealed a significant correlation between the enhancement of T c onset and the “strange metal” behavior in the normal state, characterized by a linear-in-temperature resistivity. As the film’s oxidation state approached optimality, the normal-state transport properties evolved from Fermi-liquid-like behavior toward strange-metal behavior. Additionally, the team employed mutual inductance measurements to perform the in-depth investigation of the system’s vortex dynamics. Unlike highly anisotropic, quasi-two-dimensional cuprate superconductors, the (La,Pr) 3 Ni 2 O 7 thin film system exhibits remarkably strong interlayer coupling and distinct three-dimensional characteristics. This provides crucial experimental evidence for understanding the formation of the macroscopic superconducting state in nickelates.
This advancement not only pushes the T c onset of ambient-pressure nickelates into the 60 K regime but also establishes an ideal experimental platform for exploring the mechanism of high-temperature superconductivity through high-quality thin-film samples.
National Science Review
Experimental study