Chirality and $Z_2$ vortices in an Heisenberg spin model on the kagomé lattice

Abstract

The phase diagram of the classical \jj model on the \kag lattice is investigated using extensive \mc simulations. In a realistic range of parameters, this model has a low-temperature chiral-ordered phase without long-range spin order. We show that the critical transition marking the destruction of chiral order is preempted by the first order proliferation of \Zdeux point defects. The core energy of these vortices appears to vanish when approaching the T=0 phase boundary, where both \Zdeux defects and gapless magnons contribute to disordering the system at very low temperature. This situation might be typical of a large class of frustrated magnets. Possible relevance for real materials is also discussed.

4 pages, 4 figures

References in corpus (8)

• Quantum criticality beyond the Landau-Ginzburg-Wilson paradigm
• Spin Dynamics of the Spin-1/2 Kagome Lattice Antiferromagnet ZnCu_3(OH)_6Cl_2
• Order by disorder and spiral spin liquid in frustrated diamond lattice antiferromagnets
• Valence Bond Solids and Their Quantum Melting in Hard-Core Bosons on the Kagome Lattice
• Unconventional Dynamics in Triangular Heisenberg Antiferromagnet NaCrO2
• Twelve sublattice ordered phase in the J1-J2 model on the kagome lattice
• Direct evidence for a dynamical ground state in the highly frustrated Tb${}_2$Sn${}_2$O${}_7$ pyrochlore
• Low temperature broken symmetry phases of spiral antiferromagnets

Cited by in corpus (3)

• Scalar spin chirality and quantum Hall effect on a triangular lattice
• Octupolar ordering of classical kagome antiferromagnets in two and three dimensions
• Thermal destruction of chiral order in a two-dimensional model of coupled trihedra