Spatially anisotropic Heisenberg kagome antiferromagnet

Abstract

We study the quasi-one-dimensional limit of the spin-1/2 quantum Heisenberg antiferromagnet on the kagome lattice. The lattice is divided into antiferromagnetic spin chains (exchange $J$) that are weakly coupled via intermediate ``dangling'' spins (exchange ${J}^{\ensuremath{'}}$). Using one-dimensional bosonization, renormalization-group methods, and current algebra techniques, the ground state is determined in the limit ${J}^{\ensuremath{'}}⪡J$. We find that the dangling spins and chain spins form a spiral with $O(1)$ and $O({J}^{\ensuremath{'}}/J)$ static moments, respectively, atop of which the chain spins exhibit a smaller $O[{({J}^{\ensuremath{'}}/J)}^{2}]$ antiferromagnetically ordered component along the axis perpendicular to the spiral plane.