Chiral Electron-Hole Pairing as the Origin of Anomalous Quasiparticle Dispersions in Unconventional Superconductors

The microscopic pairing mechanism in unconventional superconductors remains elusive, largely because the extreme flatness of the superconducting band often obscures key energy-momentum dispersion features observed in angle-resolved photoemission spectroscopy. In this work, we re-examine high-resolution dispersion data from cuprates (Bi2212 and Bi2201) and iron-based superconductors (monolayer FeSe) to test the predictions of a newly proposed chiral electron-hole (CEH) pairing mechanism. Unlike Cooper pairs in BCS-like theories that form a single quasiparticle band with a smooth back-bending dispersion, CEH pairs exhibit a distinct two-band structure in quasiparticle dispersion with sharp cusps at the back-bending points. Our analysis identifies clear empirical signatures of these CEH-predicted features, concluding that quasiparticle dispersions in these strongly correlated materials deviate significantly from BCS-like behavior. Further comprehensive and targeted experimental strategies are proposed to definitively resolve the subtle dispersion features and rigorously test the CEH model for unconventional superconductivity.