Excitation spectra and ground state properties of the layered spin-1/2 frustrated antiferromagnets Cs_2CuCl_4 and Cs_2CuBr_4

Abstract

We use series expansion methods to study ground- and excited-state properties in the helically ordered phase of spin-1/2 frustrated antiferromagnets on an anisotropic triangular lattice. We calculate the ground state energy, ordering wavevector, sublattice magnetization and one-magnon excitation spectrum for parameters relevant to Cs_2CuCl_4 and Cs_2CuBr_4. Both materials are modeled in terms of a Heisenberg model with spatially anisotropic exchange constants; for Cs_2CuCl_4 we also take into account the additional Dzyaloshinskii-Moriya (DM) interaction. We compare our results for Cs_2CuCl_4 with unpolarized neutron scattering experiments and find good agreement. In particular, the large quantum renormalizations of the one-magnon dispersion are well accounted for in our analysis, and inclusion of the DM interaction brings the theoretical predictions for the ordering wavevector and the magnon dispersion closer to the experimental results.

arXiv comment10 pages, 8 figures

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Cited by in corpus (29)

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• Extreme sensitivity of a frustrated quantum magnet: Cs_2CuCl_4
• Global phase diagrams of frustrated quantum antiferromagnets in two dimensions: doubled Chern-Simons theory
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• Geometrical frustration in the spin liquid beta'-Me3EtSb[Pd(dmit)2]2 and the valence bond solid Me3EtP[Pd(dmit)2]2
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• Determination of effective microscopic models for the frustrated antiferromagnets Cs${}_2$CuCl${}_4$ and Cs${}_2$CuBr${}_4$ by density functional methods
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• Spin liquid phase in the semiclassical theory of the Heisenberg model on an anisotropic triangular lattice with ring exchange
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• Elastic constants and ultrasonic attenuation in the cone state of the frustrated antiferromagnet Cs_2CuCl_4
• Spin liquid phase in a spatially anisotropic frustrated antiferromagnet
• Hybridization and Decay of Magnetic Excitations in two-dimensional Triangular Lattice Antiferromagnets
• Dynamical reduction of the dimensionality of exchange interactions and the "spin-liquid" phase of $\kappa$-(BEDT-TTF)${}_{2}X$
• Ground-state and thermodynamic properties of the spin-$\frac{1}{2}$ Heisenberg model on the anisotropic triangular lattice
• Spin Casimir Effect in Non-collinear Quantum Antiferromagnets
• Interplay between spatial anisotropy and further exchange interactions in the triangular Heisenberg model
• Frustration, ring exchange, and the absence of long-range order in EtMe${}_3$Sb[Pd(dmit)${}_2$]${}_2$: from first principles to many-body theory
• Magnetic phases of the anisotropic triangular lattice Hubbard model
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