Nodeless superconductivity arising from strong (pi,pi)   antiferromagnetism in the infinite-layer electron-doped cuprate Sr1-xLaxCuO2
  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 A1-xLaxCuO2. Here we report in situ angle-resolved photoemission spectroscopy measurements of epitaxially-stabilized films of Sr1-xLaxCuO2 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. 
John W. Harter, Luigi Maritato, Daniel E. Shai, Eric J. Monkman,   Yuefeng Nie, Darrell G. Schlom, Kyle M. Shen
cond-mat.supr-con cond-mat.mtrl-sci cond-mat.str-el