Pressure-induced superconductivity in kagome metal CsCr₃Sb₅: Role of spin–orbit coupling and inter-orbital spin fluctuations

Motivated by the recent discovery of superconductivity in the kagome metal CsCr₃Sb₅ under pressure, we theoretically investigate the superconducting pairing symmetry and the impact of spin–orbit coupling (SOC) in this system. By employing an effective four-orbital tight-binding model and solving the linearized gap equation within the random phase approximation, we find that the large inter-orbital spin fluctuations enhanced by Hund’s coupling promote a superconducting gap function with E_2g symmetry. The inclusion of SOC further stabilizes this gap symmetry. Our analysis also reveals that the d_x²-y² orbital plays the dominant role in forming the superconducting pairs.