Evidence for a Lifshitz transition in electron-doped iron arsenic superconductors at the onset of superconductivity. - Chang Liu; Kondo, Takeshi; Fernandes, Rafael M.; Palczewski, Ari D.; Eun Deok Mun; Ni, Ni; Thaler, Alexander N.; Bostwick, Aaron; Rotenberg, Eli; Schmalian, Jörg; Bud'ko, Sergey L.; Canfield, Paul C.; et al. (Nature Physics, 2010)