Nodeless superconductivity arising from strong (pi,pi) antiferromagnetism in the infinite-layer electron-doped cuprate Sr1-xLaxCuO2

TL;DR

This study reveals that strong (pi,pi) antiferromagnetism causes Fermi surface reconstruction in Sr1-xLaxCuO2, leading to nodeless superconductivity, unifying understanding across electron-doped cuprates.

Contribution

It demonstrates that (pi,pi) antiferromagnetism induces nodeless superconductivity in electron-doped cuprates without changing the order parameter symmetry.

Findings

Fermi surface reconstruction pushes hole pockets below the Fermi level.

Nodeless superconductivity occurs without symmetry change.

Universal behavior across electron-doped cuprates.

Abstract

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.