Raman scattering for triangular lattices spin-1/2 Heisenberg antiferromagnets

TL;DR

This paper develops a theoretical framework for Raman scattering in spin-1/2 triangular lattice antiferromagnets, analyzing spectral features across different exchange ratios to identify quantum fluctuation effects.

Contribution

It introduces a Raman operator for various geometries and systematically investigates spectral responses as a function of exchange interactions, including polarization effects.

Findings

Spectra computed for different J2/J1 ratios reveal signatures of quantum fluctuations.

Polarization dependence helps detect ground state instabilities.

Results provide insights into magnetic excitations in triangular lattice antiferromagnets.

Abstract

Motivated by various spin-1/2 compounds like Cs$_2$CuCl$_4$ or $\kappa$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$, we derive a Raman-scattering operator {\it \`a la} Shastry and Shraiman for various geometries. For T=0, the exact spectra is computed by Lanczos algorithm for finite-size clusters. We perform a systematic investigation as a function of $J_2/J_1$, the exchange constant ratio: ranging from $J_2=0$, the well known square-lattice case, to $J_2/J_1=1$ the isotropic triangular lattice. We discuss the polarization dependence of the spectra and show how it can be used to detect precursors of the instabilities of the ground state against quantum fluctuations.