Direct transition from a fractional Chern insulator to a topological superconductor

arXiv:2611.08475

Taige Wang

We find numerical evidence for a direct continuous transition from a Laughlin fractional Chern insulator (FCI) to a $c_-=3/2$ topological superconductor (TSC), driven by increasing bandwidth at filling $ν=1/3$ in a repulsively interacting Chern band. At the critical point, the electron correlation length diverges at momentum away from the reference Fermi surface. We develop a generalized theory of superconducting-vortex proliferation for this transition. Magnetic translation organizes the vortices into six valleys, so translation-preserving proliferation requires additional gauge fields. The resulting theory reproduces the momentum structure of the critical spectrum and captures the divergent electron correlation. Upon doping away from commensurate filling, the theory gives rise to a superconducting dome. These results are consistent with an anyonic origin of the topological superconductivity in the absence of a weak-coupling Fermi-surface instability.