Daily Overview: This post sorts papers by relevance to nickelate superconductors. Summaries are AI-generated and may contain errors. arXiv submission processing window: times are unavailable (UTC).

1. Raman response in superconducting multiorbital systems with application to nickelates

Summary: This study systematically analyzes the Raman response of superconducting multi-orbital systems using electronic Raman scattering methods, with nickelates as the application target. For three models—a single-layer and a bilayer two-orbital model involving d_{x^2-y^2} and d_{z^2} orbitals, and a bilayer single-orbital model with only d_{x^2-y^2} orbitals—multiple pairing symmetries including d-wave, s±-wave, and s-wave are considered, and the response characteristics under various Raman symmetries (A1g, B1g, B2g) are calculated. In the two-orbital models, a full multi-orbital approach is employed, incorporating both intra-orbital and inter-orbital scattering, and compared with the additive approximation that simply sums the Raman responses of individual bands. The results reveal distinct fingerprint features in the Raman spectra for different pairing symmetries and model structures, with the full multi-orbital calculations uncovering inter-orbital mixing effects that the additive approximation may overlook. These findings help clarify the minimal model for nickelate superconductivity, determine the magnitude and symmetry of their superconducting gaps, and provide a general theoretical framework for Raman experimental analysis of other multi-orbital superconductors, such as iron-based superconductors.