Theory of the algebraic vortex liquid in an anisotropic spin-1/2 triangular antiferromagnet

We explore spin-1/2 triangular antiferromagnets with both easy-plane and lattice exchange anisotropies by employing a dual vortex mapping followed by a fermionization of the vortices. Over a broad range of exchange anisotropy, this approach leads naturally to a "critical" spin liquid-the algebraic vortex liquid-which appears to be distinct from other known spin liquids. We present a detailed characterization of this state, which is described in terms of noncompact QED3 with an emergent SU(4) symmetry. Descendant phases of the algebraic vortex liquid are also explored, which include the Kalmeyer-Laughlin spin liquid, a variety of magnetically ordered states such as the well-known coplanar spiral state, and supersolids. In the range of exchange anisotropy where the "square lattice" Neel ground state arises, we demonstrate that anomalous "roton" minima in the excitation spectrum recently reported in series expansions can be accounted for within our approach.