Nodeless Superconducting Phase Arising from a Strong (pi, pi) Antiferromagnetic Phase in the Infinite- Layer Electron- Doped Sr1-xLaxCuO2 Compound

The asymmetry between electron and hole doping remains one of the central issues in high-temperature cuprate superconductivity, but our understanding of the electron-doped cuprates has been hampered by apparent discrepancies between the only two known families: Re2-xCexCuO4 and A(1-x)La(x)CuO(2). Here we report in situ angle-resolved photoemission spectroscopy measurements of epitaxially stabilized Sr1-xLaxCuO2 thin films synthesized by oxide molecular-beam epitaxy. Our results reveal a strong coupling between electrons and (pi, pi) antiferromagnetism that induces a Fermi surface reconstruction which pushes the nodal states below the Fermi level. This removes the hole pocket near (pi/2, pi/2), realizing nodeless superconductivity without requiring a change in the symmetry of the order parameter and providing a universal understanding of all electron-doped cuprates. DOI: 10.1103/PhysRevLett.109.267001