Theory of Néel and valence-bond solid phases on the kagome lattice of Zn paratacamite.

Theory of Néel and Valence - Bond - Solid Phases on the Kagome Lattice of

The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters. Theory of Néel and valence-bond-solid phases on the kagome lattice of Zn-paratacamite. Recently, neutron scattering data on powder samples of Zn-paratacamite, ZnxCu4−x(OH)6Cl2, with small Zn concentration has been interpreted as evidence for valence bond solid and Néel or...

Theory of Néel and Valence - Bond - Solid Phases on the Kagome

Valence bond solid phases in a cubic antiferromagnet.

We report on a valence bond projector Monte Carlo simulation of the cubic lattice quantum Heisenberg model with additional higher-order exchange interactions in each unit cell. The model supports two different valence bond solid (VBS) ground states. In one of these states, the dimer pattern is a three-dimensional analogue of the columnar pattern familiar from two dimensions. In the other, the d...

Frustrated Quantum Magnets

A description of different phases of two dimensional magnetic insulators is given. The first chapters are devoted to the understanding of the symmetry breaking mechanism in the semi-classical Néel phases. Order by disorder selection is illustrated. All these phases break SU(2) symmetry and are gapless phases with ∆Sz = 1 magnon excitations. Different gapful quantum phases exist in two dimension...

Emergent SO(5) Symmetry at the Néel to Valence-Bond-Solid Transition.

We show numerically that the "deconfined" quantum critical point between the Néel antiferromagnet and the columnar valence-bond solid, for a square lattice of spin 1/2, has an emergent SO(5) symmetry. This symmetry allows the Néel vector and the valence-bond solid order parameter to be rotated into each other. It is a remarkable (2+1)-dimensional analogue of the SO(4)=[SU(2)×SU(2)]/Z(2) symmetr...