Nodeless Superconducting Phase Arising from a Strong (π, π) Antiferromagnetic Phase in the Infinite-Layer Electron-Doped Sr_(1-x)La_x.CuO_2 Compound

摘要

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: Re_(2-x)Ce_xCuO_4 and A_(1-x)La_xCuO_2. Here we report in situ angle-resolved photoemission spectroscopy measurements of epitaxially stabilized Sr_(1-x)La_xCuO_2 thin films synthesized by oxide molecular-beam epitaxy. Our results reveal a strong coupling between electrons and (π, π) antiferromagnetism that induces a Fermi surface reconstruction which pushes the nodal states below the Fermi level. This removes the hole pocket near (π/2, π/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.