Strong Three-magnon Scattering in Cuprates by Resonant X-rays

TL;DR

This paper demonstrates that Resonant Inelastic X-ray scattering (RIXS) can effectively detect three-magnon excitations in cuprates, with the tri-magnon signal often surpassing single- and bi-magnon signals, especially at the copper M-edge.

Contribution

It reveals that RIXS is highly sensitive to three-magnon excitations in cuprates, showing that tri-magnon scattering can dominate magnetic signals at certain edges.

Findings

Tri-magnon scattering intensity exceeds bi-magnon at Cu L-edge.

At low transferred momentum, tri-magnon exceeds single-magnon intensity.

Tri-magnon scattering dominates over other magnetic channels at Cu M-edge.

Abstract

We show that Resonant Inelastic X-ray scattering (RIXS) is sensitive to three-magnon excitations in cuprates. Even if it requires three electrons to simultaneously flip their spin, the RIXS tri-magnon scattering amplitude is not small. At the Cu $L$-edge its intensity is generally larger than the bi-magnon one and at low transferred momentum even larger than the single-magnon intensity. At the copper $M$-edge the situation is yet more extreme: in this case three-magnon scattering is dominating over all other magnetic channels.