Spin-resolved impurity resonance states in electron-doped cuprate superconductors

TL;DR

This paper investigates impurity-induced electronic states in electron-doped cuprate superconductors to differentiate between competing theories of the non-monotonic d-wave gap using spin-polarized scanning tunneling microscopy.

Contribution

It identifies distinct local density of states signatures for different superconducting gap scenarios, proposing a method to determine the true physical origin of the non-monotonic gap.

Findings

Local density of states differs between scenarios with higher harmonic d-wave and coexisting antiferromagnetic order.

Spin-polarized STM can distinguish these scenarios based on impurity resonance states.

Provides a diagnostic tool for understanding the pairing symmetry in electron-doped cuprates.

Abstract

With the aim at understanding the non-monotonic $d_{x^{2}-y^{2}}$-wave gap, we analyze the local electronic structure near impurities in the electron-doped cuprate superconductors. We find that the local density of states near a non-magnetic impurity in the scenario of $d_{x^{2}-y^{2}}$-wave superconductivity with higher harmonics is qualitatively different from that obtained from the $d_{x^{2}-y^{2}}$-wave superconductivity coexisting with antiferromagnetic spin density wave order. We propose that spin-polarized scanning tunneling microscopy measurements can distinguish the two scenarios and shed light on the real physical origin of a non-monotonic $d_{x^{2}-y^{2}}$-wave gap.