Raman Scattering from Frustrated Quantum Spin Chains

TL;DR

This paper analyzes magnetic Raman scattering in frustrated spin-1/2 chains, using a spinless-fermion mean-field theory, revealing a broad four-spinon continuum at low temperatures and a quasi-elastic line at high temperatures, aligning well with experiments.

Contribution

It introduces a spinless-fermion mean-field approach to analyze Raman scattering in frustrated spin chains, connecting theoretical predictions with experimental observations.

Findings

Broad inelastic four-spinon continuum observed at low temperatures.

Quasi-elastic line develops at high temperatures.

Good agreement between theory and experimental Raman spectra.

Abstract

Magnetic Raman scattering from a frustrated spin-1/2 Heisenberg-chain is considered with a focus on the uniform phase of the spin-Peierls compound CuGeO_3. The Raman intensity is analyzed in terms of a Loudon-Fleury scattering process using a spinless-fermion mean-field theory developed for the frustrated spin-chain. A comparison to experimental data is presented and the frustration and temperature dependence is studied. In good agreement with observed spectra a broad inelastic four-spinon continuum is found at low temperatures above the spin-Peierls transition. At high temperatures the intensity develops a quasi-elastic line analogous to experiment.