The influence of chemical doping on bilayer nickelates

Hualei Sun
School of Science, Sun Yat-sen University, 518107, Shenzhen, China

High-temperature superconductivity has always attracted research interests in condensed matter physics. The discovery of high-temperature superconductivity at 80 K in pressurized bilayer La₃Ni₂O₇ has pioneered a new research frontier for high-temperature superconductors[1]. In this report, I will provide an overview of our high-pressure study on La₃Ni₂O₇ and our recent two investigations into further elevating T_c in La₃Ni₂O₇ through chemical doping. The first investigation explores Sm substitution: it compresses lattice parameters, enhances structural distortion, and raises the optimal T_c to 89.2 K in La_1.5Sm_1.5Ni₂O₇ at 37.1 GPa[2]. The other investigation focuses on La_3−xNd_xNi₂O₇ (0 ≤ x ≤ 2.4) with record Nd doping, achieving a T_c of 93 K via transport measurements and 98 ± 2 K by radio-frequency detection in high-doping samples[3]. Both studies highlight isovalent rare-earth doping as an effective strategy to modulate structural and superconducting properties, providing critical insights for further enhancing T_c in nickelate superconductors.

[1]Hualei Sun, Mengwu Huo, Guang-Ming Zhang, and Meng Wang et al, Signatures of superconductivity near 80 K in a nickelate under high pressure. Nature 621, 493-498 (2023).
[2]Qingyi Zhong, Junfeng Chen, Hualei Sun, and Meng Wang et al. Evolution of the superconductivity in pressurized La3-xSmxNi2O7. arXiv:2510.13342 (2025).

[3]Zhengyang Qiu, Junfeng Chen, Viktor Struzhkin, Hualei Sun, Meng Wang et al. Interlayer coupling enhanced superconductivity near 100 K in La3-xNdxNi2O7. arXiv: 2510.12359 (2025).