Koji Kudo@Kyushu Univ. will be talking about topological superconductivity. Join us.
Condensed Matter Seminar
物性論セミナー 2026年3月30日 (月), Mar 30 (Mon), 2026, 15:00-16:00
自然系学系棟D棟3階: 301号室 (Institutes of Natural Sciences Bldg. D 301)
Repulsive-interaction-driven topological superconductivity in a quantum Hall-superconductor hybrid
Koji Kudo, Kyushu University
Topological superconductivity (TSC) is predicted to arise when a topological state, such as surface states of topological insulators, is proximity-coupled to an s-wave superconductor. Given that a Landau level is a prototypical topological band, one might expect that coupling it to an s-wave superconductor would produce TSC. However, that turns out not to be the case in the simplest model [1,2]. In this work, we demonstrate that repulsive electron-electron interactions drive TSC in this hybrid. This is counterintuitive, as one would expect a repulsive interaction to be antithetical to superconductivity. As the strength of the interactions is increased, the system eventually transitions into a composite Fermi liquid (CFL) state, suggesting that the system can be viewed as a CFL proximity-coupled to an s-wave superconductor [3].
[1] R. V. Mishmash, A. Yazdani, and M. P. Zaletel, Phys. Rev. B 99, 115427 (2019).[2] G. Chaudhary and A. H. MacDonald, Phys. Rev. B 101, 024516 (2020).
[3] K. Kudo, R. Nakai, H. Isobe, J. K. Jain, and K. Nomura, arXiv:2510.04700