Nickelate superconductors provide a valuable new platform for the study of unconventional superconductivity that is complementary to the cuprates. One of the central puzzles about high-temperature superconductors is what factors determine the scale of their superconducting transition temperature (Tc). To address this question for infinite-layer nickelates, we present a systematic mutual inductance study of the superfluid density across the doping-dependent superconducting dome of Nd1−xSrxNiO2. We observe a weak superfluid stiffness that exhibits an approximately square-root correlation with Tc. We also find a strong interplay between Nd magnetism and the superconducting phase, manifested as a substantial low-temperature suppression of superfluid density. These observations highlight the importance of superconducting phase fluctuations in limiting Tc and unexpectedly strong coupling between the Nd 4f moments and the superfluid.
@article{arxiv.2603.05606,
title = {Evolution of the Superfluid Density in Infinite-Layer Nickelates},
author = {Bai Yang Wang and Shannon P. Harvey and Kyuho Lee and Yijun Yu and Yonghun Lee and Motoki Osada and Chaitanya Murthy and Srinivas Raghu and Harold Y. Hwang},
journal= {arXiv preprint arXiv:2603.05606},
year = {2026}
}