Year: 2007
Type: article
Abstract: Although magnetically ordered at low temperatures, the spin-$\frac{1}{2}$ triangular antiferromagnet ${\mathrm{Cs}}_{2}\mathrm{Cu}{\mathrm{Cl}}_{4}$ exhibits remarkable spin dynamics that strongly suggest proximity to a spin-liquid phase. Here we ask whether a proximate spin liquid may also occur in an applied magnetic field, leaving a similar imprint on the dynamical spin correlations of this material. Specifically, we explore a spatially anisotropic Heisenberg spin-$\frac{1}{2}$ triangular antiferromagnet at $\frac{1}{3}$ magnetization from a dual vortex perspective, and indeed find a ``critical'' spin-liquid phase described by quantum electrodynamics in $(2+1)$-dimensions with an emergent SU(6) symmetry. A number of nontrivial predictions follow for the dynamical spin structure factor in this ``algebraic vortex liquid'' phase, which can be tested via inelastic neutron scattering. We also discuss how well-studied ``up-up-down'' magnetization plateaus can be captured within our approach, and further predict the existence of a stable gapless solid phase in a weakly ordered up-up-down state. Finally, we predict several anomalous ``roton'' minima in the excitation spectrum in the regime of lattice anisotropy where the canted N\'eel state appears.
Source: Physical Review B
Authors: Jason Alicea, Matthew P. A. Fisher
Language: Latvian
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2007695154