Algebraic Vortex Liquid in Spin-1/2Triangular Antiferromagnets: Scenario forCs2CuCl4

Motivated by inelastic neutron scattering data on ${\mathrm{Cs}}_2{\mathrm{CuCl}}_4$, we explore spin-$1/2$ triangular lattice antiferromagnets with both spatial and easy-plane exchange anisotropies, the latter due to an observed Dzyaloshinskii-Moriya interaction. Exploiting a duality mapping followed by a fermionization of the dual vortex degrees of freedom, we find a novel critical spin-liquid phase described in terms of Dirac fermions with an emergent global SU(4) symmetry minimally coupled to a noncompact U(1) gauge field. This “algebraic vortex liquid” supports gapless spin excitations and universal power-law correlations in the dynamical spin structure factor which are consistent with those observed in ${\mathrm{Cs}}_2{\mathrm{CuCl}}_4$. We suggest future neutron scattering experiments that should help distinguish between the algebraic vortex liquid and other spin liquids and quantum critical points previously proposed in the context of ${\mathrm{Cs}}_2{\mathrm{CuCl}}_4$.