Spin Structure Factor of the Frustrated Quantum Magnet Cs_2CuCl_4

TL;DR

This paper investigates the ground state and neutron structure factor of the frustrated quantum magnet Cs_2CuCl_4 using spin-wave theory, providing insights into its magnetic properties and comparing theoretical results with experimental data.

Contribution

It presents a detailed 1/S expansion analysis of the ground state and neutron structure factor for Cs_2CuCl_4, incorporating interactions and anisotropies, and compares results with neutron scattering experiments.

Findings

Neutron structure factor matches experimental data with adjusted parameters.

Calculated ground state energy and magnetization to order 1/S^2.

Identified the impact of anisotropy and Dzyaloshinskii-Moriya interactions.

Abstract

The ground state properties and neutron structure factor for the two-dimensional antiferromagnet on the triangular lattice, with uni-directional anisotropy in the nearest-neighbor exchange couplings and a weak Dzyaloshinskii-Moriya (DM) interaction, are studied. This Hamiltonian has been used to interpret neutron scattering measurements on the spin 1/2 spiral spin-density-wave system, Cs_2CuCl_4, [R. Coldea, et al., Phys. Rev. B 68, 134424 (2003)]. Calculations are performed using a 1/S expansion, taking into account interactions between spin-waves. The ground state energy, the shift of the ordering wave-vector, Q, and the local magnetization are all calculated to order 1/S^2. The neutron structure factor, obtained using anharmonic spin-wave Green's functions to order 1/S, is shown to be in reasonable agreement with published neutron data, provided that slightly different parameters are used for the exchange and DM interactions than those inferred from measurements in high magnetic field.