Two-magnon Raman scattering in a spin density wave antiferromagnet

TL;DR

This paper models two-magnon Raman scattering in a spin density wave antiferromagnet, revealing how resonant enhancement and vertex interactions produce spectra similar to experimental data in cuprates.

Contribution

It introduces a microscopic analysis of photon-magnon coupling and combines magnon interactions with resonance effects to accurately reproduce experimental Raman spectra.

Findings

Resonant enhancement significantly increases two-magnon intensity.

The model reproduces the shape of experimental Raman signals in cuprates.

Comparison shows differences from the traditional Loudon-Fleury approach.

Abstract

We present the results for a model calculation of resonant two-magnon Raman scattering in a spin density wave (SDW) antiferromagnet. The resonant enhancement of the two-magnon intensity is obtained from a microscopic analysis of the photon-magnon coupling vertex. By combining magnon-magnon interactions with `triple resonance` phenomena in the vertex function the resulting intensity line shape is found to closely resemble the measured two-magnon Raman signal in antiferromagnetic cuprates. Both, resonant and non-resonant Raman scattering are discussed for the SDW antiferromagnet and a comparison is made to the conventional Loudon-Fleury theory of two-magnon light scattering.