Low-temperature properties of two-dimensional frustrated quantum antiferromagnets

Though much of the recent work on 2D quantum canted antiferromagnets has been devoted to the study of disordered states, there is evidence that some of these systems have Néel ground states, even for spin 1/2. Following Chakravarty, Halperin, and Nelson, we study the quantum nonlinear sigma model suited to these systems and obtain, for the correlation length, ξ=${\mathit{C}}_{\xi }$[A/(${\mathit{k}}_{\mathit{B}}$T${)}^{1/2}$]${\mathit{e}}_{\mathit{B}}^{2\mathrm{\pi }\mathit{B}/\mathit{k}}$T, where A and B depend on the spin stiffness and spin-wave velocities renormalized by quantum fluctuations. We discuss experiments on ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ adsorbed on Grafoil.