Understanding reduced NMR signals in Sr₂RuO₄

The superconducting order parameter of Sr₂RuO₄ has been a topic of recent interest, as new NMR experiments are in contradiction with the previously proposed p_x±ip_y triplet superconducting state [1]. The multi-orbital nature of the Fermi surface, in combination with the Hund’s and spin-orbit coupling, allows various types of superconducting order parameters. We propose inter-orbital spin triplet pairing based on the Hund’s and spin-orbit coupling [2], and study the NMR signals with and without uniaxial strain. These results are compared with recent NMR experiments, and future experiments which can test the validity of the proposed pairing symmetry are also discussed.
[1] A. Pustogow et al., arXiv:1904.00047 (2019).
[2] C. M. Puetter and H.-Y. Kee, EPL 98, 27010 (2012).