Research progress on identification of the high T_c superconductivity and superconducting phase in La₃Ni₂O₇ under pressure

We introduce experimental investigations on the high T_c superconductivity at 80 K in the bilayer nickelate La₃Ni₂O₇ under a 14 GPa pressure. The superconductivity emerges coincidently with a structural transition from Amam to I4/mmm. Both zero resistance and diamagnetic response, which are essential for superconductivity, were observed. A multislice electron ptychography technique was employed to visualize the oxygen. The results confirm the superconducting phase is the bilayer phase of La₃Ni₂O₇ with low oxygen vacancies.

Work at SYSU was supported by the National Natural Science Foundation of China (Grants No. 12425404 and 12174454), the National Key Research and Development Program of China (Grant No. 2023YFA1406500), the Guangdong Basic and Applied Basic Research Funds (Grant No. 2024B1515020040), Guangzhou Basic and Applied Basic Research Funds (Grant No. 2024A04J6417), and Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices (Grant No. 2022B1212010008).

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