title: Three-Dimensional Crystallization of Vortex Strings in Frustrated Quantum Magnets.
abstract: We demonstrate that frustrated exchange interactions can produce exotic 3D crystals of vortex strings near the saturation field (H=H(sat)) of body- and face-centered cubic Mott insulators. The combination of cubic symmetry and frustration leads to a magnon spectrum of the fully polarized spin state (H>H(sat)) with degenerate minima at multiple noncoplanar Q vectors. This spectrum becomes gapless at the quantum critical point H=H(sat) and the magnetic ordering below H(sat) can be formally described as a condensate of a dilute gas of bosons. By expanding in the lattice gas parameter, we find that different vortex crystals span sizable regions of the phase diagrams for isotropic exchange and are further stabilized by symmetric exchange anisotropy.
authors.affiliation: Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA.
authors.forename: Zhentao
authors.initials: Z
authors.lastname: Wang
authors.affiliation: iTHES Research Group and Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Kamiya
authors.affiliation: Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA.
authors.forename: Andriy H
authors.initials: AH
authors.lastname: Nevidomskyy
authors.affiliation: Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: Cristian D
authors.initials: CD
authors.lastname: Batista