Statistics of spinons in the spin-liquid phase ofCs2CuCl4

Abstract

Motivated by a recent experiment on ${\mathrm{Cs}}_{2}{\mathrm{CuCl}}_{4}$ [Coldea et al., Phys. Rev. Lett. 86, 1335 (2001)], we study the spin dynamics of the spin-liquid phase of the $\mathrm{s}\mathrm{p}\mathrm{i}\mathrm{n}\ensuremath{-}\frac{1}{2}$ frustrated Heisenberg antiferromagnet on the anisotropic triangular lattice. There have been two different proposals for the spin-liquid phase of ${\mathrm{Cs}}_{2}{\mathrm{CuCl}}_{4}.$ These spin-liquid states support different statistics of spinons; the bosonic $\mathrm{Sp}(N)$ large-N mean-field theory predicts bosonic spinons, while the SU(2) slave-boson mean-field theory leads to fermionic spinons. We compute the dynamical spin structure factor for both types of spin-liquid state at zero and finite temperatures. While at zero temperature both theories agree with experiment on a qualitative level, they show substantial differences in the temperature dependence of the dynamical spin structure factor.