Anomalous correlation effects and unique phase diagram of electron-doped FeSe revealed by photoemission spectroscopy

Electron doping is a powerful way to induce quantum phase transitions in materials and explore exotic states of matter. Here, Wen et al. present carefully-controlled potassium dosing in FeSe films and FeSe0.93S0.07bulk, which enhances superconductivity and induces other anomalous phases, revealing a complex phase diagram.