Berry Phase Coupling and the Cuprate Neutron Scattering Resonance

TL;DR

This paper investigates how coupling between different spin fluctuation channels affects the neutron scattering resonance in cuprate superconductors, revealing conditions under which the resonance is suppressed or shifted.

Contribution

It provides a theoretical analysis of particle-hole and particle-particle coupling effects on the INSR in cuprates, including weak and strong interaction regimes.

Findings

Interchannel coupling can eliminate the resonance in weak interactions.

Resonance frequency approaches zero near magnetic instability in strong interactions.

Comparison with iron pnictides offers insights into cuprate physics.

Abstract

We examine the influence of coupling between particle-hole and particle-particle spin fluctuations on the inelastic neutron scattering resonance (INSR) in cuprate superconductors in both weak and strong interaction limits. For weak-interactions in the particle-hole channel, we find that the interchannel coupling can eliminate the resonance. For strong interactions which drive the system close to a $\bm{Q}=(\pi,\pi)$ magnetic instablity, the resonance frequency always approaches zero but its value is influenced by the interchannel coupling. We comment on constraints imposed on cuprate physics by the INSR phenomenology, and a comparison between the cuprates and the newly-discovered iron pnictide superconductors is discussed.