Raman scattering in a Heisenberg S=1/2 antiferromagnet on the anisotropic triangular lattice

TL;DR

This study explores how two-magnon Raman scattering in an anisotropic triangular lattice antiferromagnet reveals sensitive dependence on interactions and geometry, offering insights into ground-state properties and potential spin-liquid behavior.

Contribution

It demonstrates the polarization dependence of Raman scattering in anisotropic triangular antiferromagnets, contrasting with isotropic cases, and suggests Raman spectroscopy as a probe for ground-state properties.

Findings

Raman response varies with magnon interactions and scattering geometry

Polarization dependence distinguishes anisotropic from isotropic cases

Raman spectroscopy can probe time-reversal symmetry in the ground state

Abstract

We investigate the two-magnon Raman scattering from an anisotropic S=1/2 triangular Heisenberg antiferromagnet Cs2CuCl4. We find that the Raman response is very sensitive to magnon-magnon interactions and to scattering geometries, a feature that is in remarkable contrast with the polarization-independent Raman signal from the isotropic triangular Heisenberg antiferromagnet. Since a spin-liquid ground state gives rise to a similar rotationally invariant Raman response, our results on the polarization dependence of the scattering spectrum suggest that Raman spectroscopy provides a useful probe, complementary to neutron scattering, of the ground-state properties of Cs2CuCl4, particularly whether the time-reversal symmetry is broken in the ground state.