Direct Observation of Non-Monotonic dx2-y2-Wave Superconducting Gap in Electron-Doped High-Tc Superconductor Pr0.89LaCe0.11CuO4

TL;DR

This study uses high-resolution photoemission spectroscopy to reveal a non-monotonic dx2-y2-wave superconducting gap in Pr0.89LaCe0.11CuO4, supporting spin-mediated pairing in electron-doped high-Tc superconductors.

Contribution

It provides direct experimental evidence of a non-monotonic superconducting gap symmetry, highlighting the role of antiferromagnetic spin fluctuations in electron-doped cuprates.

Findings

Superconducting gap deviates from monotonic dx2-y2 symmetry.

Maximum gap occurs at the hot spot, not the zone boundary.

Results support spin-mediated pairing mechanism.

Abstract

We performed high-resolution angle-resolved photoemission spectroscopy on electron-doped high-Tc superconductor Pr0.89LaCe0.11CuO4 to study the anisotropy of the superconducting gap. The observed momentum dependence is basically consistent with the dx2-y2-wave symmetry, but obviously deviates from the monotonic dx2-y2 gap function. The maximum gap is observed not at the zone boundary, but at the hot spot where the antiferromagnetic spin fluctuation strongly couples to the electrons on the Fermi surface. The present experimental results unambiguously indicate the spin-mediated pairing mechanism in electron-doped high-Tc superconductors.