Relationship among superconductivity, pseudogap, and high-energy magnetic fluctuations in a model high-Tc superconductor from electronic Raman scattering

TL;DR

This study uses electronic Raman scattering to explore the interplay between superconductivity, pseudogap phenomena, and high-energy magnetic fluctuations in a model high-Tc cuprate superconductor, revealing feedback mechanisms that occur both below and above Tc.

Contribution

It provides new insights into how magnetic fluctuations influence superconductivity and pseudogap behavior in cuprates through Raman spectroscopy observations.

Findings

High-energy magnetic fluctuations are enhanced below Tc.

Superconducting gap and pairing peak appear in Raman spectra.

Feedback mechanisms are active above Tc in underdoped samples.

Abstract

We use electronic Raman scattering to study the model single-layer cuprate superconductor HgBa2CuO4+d. In an overdoped sample, we observe a pronounced amplitude enhancement of a high-energy peak related to two-magnon excitations in insulating cuprates upon cooling below the critical temperature Tc. This effect is accompanied by the appearance of the superconducting gap and a pairing peak above the gap in the Raman spectrum, and it can be understood as a consequence of feedback of the Cooper pairing interaction on the high-energy magnetic fluctuations. All of these effects occur already above Tc in two underdoped samples, demonstrating a related feedback mechanism associated with the pseudogap.