Disentangling single-particle gap by electronic Raman absorption in electron-doped cuprates

TL;DR

This paper uses electronic Raman spectroscopy and a microscopic model to distinguish between superconducting and antiferromagnetic contributions to the quasiparticle gap in electron-doped cuprates, clarifying the nature of the non-monotonic gap.

Contribution

It introduces a method to disentangle SC and AFM gap contributions in Raman spectra, aiding understanding of the coexistence of orders in electron-doped cuprates.

Findings

Raman spectra can separate SC and AFM gap contributions.

The effective gap's non-monotonicity can be explained by coexistence of orders.

The method clarifies the origin of the quasiparticle gap in doped cuprates.

Abstract

In the under- to optimal-doping regimes of electron-doped cuprates, it was theoretically suspected that there is a coexistence of superconducting (SC) and antiferromagnetic (AFM) orders. The quasi-particle excitations could be gapped by both orders, and the effective gap is non-monotonic d-wave-like in the momentum space. Alternatively the gap was also speculated as a pure pairing gap. Using an effective microscopic model, we consider the manifestation of the quasi-particle gap in the electronic Raman spectra in a range of doping levels, where the relative strength of the SC and AFM order parameters varies. We demonstrate that from the electronic Raman spectra the effective single-particle gap can be disentangled into contributions from the two distinctive orders. This would help to tell whether the non-monotonic gap is due to the coexistence of SC and AFM orders.