Two-Fermi-surface superconducting state and a nodal d-wave gap in the electron-doped Sm(1.85)Ce(0.15)CuO(4-d) cuprate superconductor

TL;DR

This study uses laser ARPES to reveal a nodal hole-pocket Fermi-surface and d-wave superconducting gap in electron-doped Sm(1.85)Ce(0.15)CuO(4-d), indicating coexistence of antiferromagnetism and superconductivity.

Contribution

It demonstrates the coexistence of long-range antiferromagnetism and superconductivity with a two-Fermi-surface structure in electron-doped cuprates.

Findings

Nodal hole-pocket Fermi-surface exists in both normal and superconducting states.

Long-range antiferromagnetism causes the hole-pocket Fermi-surface.

Superconducting gap exhibits d-wave symmetry.

Abstract

We report on laser-excited angle-resolved photoemission spectroscopy (ARPES) in the electron-doped cuprate Sm(1.85)Ce(0.15)CuO(4-d). The data show the existence of a nodal hole-pocket Fermi-surface both in the normal and superconducting states. We prove that its origin is long-range antiferromagnetism by an analysis of the coherence factors in the main and folded bands. This coexistence of long-range antiferromagnetism and superconductivity implies that electron-doped cuprates are two-Fermi-surface superconductors. The measured superconducting gap in the nodal hole-pocket is compatible with a d-wave symmetry.