Repulsive-interaction-driven topological superconductivity in a Rashba-coupled Landau level proximity-coupled to a type-II s-wave superconductor

Noninteracting electrons partially occupying a Rashba-coupled Landau level (LL) have been predicted to exhibit topological superconductivity (TSC) when proximity-coupled to a type-II s-wave superconductor along with an external potential [1] or an unconventional Abrikosov lattice [2], or disorder [3]. Here, we establish an alternative pathway for realizing TSC in such hybrid systems. We demonstrate that a repulsive electron-electron interaction drives TSC at half-filling in a Rashba-coupled LL proximity-coupled to an s-wave superconductor. As the interaction strength increases, the system undergoes a transition to a composite Fermi liquid (CFL) state, suggesting that our system can be viewed as a hybrid of CFL and a superconductor [4].

[1] R. V. Mishmash, A. Yazdani, and M. P. Zaletel, Phys. Rev. B 99, 115427 (2019); J. Schirmer, J. K. Jain, and C. X. Liu, Phys. Rev. B 109, 134518 (2024).

[2] G. Chaudhary and A. H. MacDonald, Phys. Rev. B 101, 024516 (2020).

[3] K. Kudo, R. Nakai, and K. Nomura, Phys. Rev. B 109, 134518 (2024).

[4] K. Kudo, R. Nakai, H. Isobe, J. K. Jain, and K. Nomura, arXiv:2510.04700