Kagome superconductors AV3Sb5 (A=K, Rb, Cs) have sparked considerable interest due to the presence of several intertwined symmetry-breaking phases within a single material. Interestingly, in a recent experiment, magnetic hysteresis was observed in the superconducting state through magnetoresistance measurements in RbV3Sb5 [Nature Comm \textbf{17}, 1310 (2026)], providing strong evidence of a spontaneous time-reversal symmetry breaking superconducting state. The magnetic hysteresis, combined with crystalline symmetry, imposes strong constraints on the possible pairing symmetries of the superconducting state. In this work, we propose that RbV3Sb5 is a nodal topological superconductor with pseudo-spin-polarized Cooper pairs. The pseudo-spin-polarized superconducting domains resemble the properties of ferromagnetic domains and induce hysteresis. Moreover, the nodal topological superconducting state possesses Majorana flat band modes at the sample boundary, which can be detected by tunneling experiments.
@article{arxiv.2501.10998,
title = {Pseudo-spin-polarized topological superconductivity in kagome RbV$_3$Sb$_5$},
author = {Xilin Feng and Zi-Ting Sun and Ben-Chuan Lin and K. T. Law},
journal= {arXiv preprint arXiv:2501.10998},
year = {2026}
}