相关论文: Weak antiferromagnetism and dimer order in quantum…
We study the ground state properties of an anisotropic, quasi-2D version of the quantum (S=1/2) pyrochlore antiferromagnet. In the presence of Dzyaloshinsky-Moriya interactions, in addition to the Heisenberg exchanges, it is shown that two…
We show that the S=1/2 pyrochlore lattice with both Heisenberg and antisymmetric, Dzyaloshinsky-Moriya (DM) interactions, can order antiferromagnetically into a state with chiral symmetry, dictated by the distribution of the DM…
Partial disorder --the microscopic coexistence of long-range magnetic order and disorder-- is a rare phenomenon, that has been experimental and theoretically reported in some Ising- or easy plane-spin systems, driven by entropic effects at…
The ground state of the S=1/2 Heisenberg antiferromagnet on the pyrochlore lattice is theoretically investigated. Starting from the limit of isolated tetrahedra, I include interactions between the tetrahedra and obtain an effective model…
Quasi-one-dimensional quantum antiferromagnets formed by a d-dimensional hypercubic lattice of weakly coupled spin-1/2 antiferromagnetic Heisenberg chains are studied by combining exact results in one-dimension and renormalization group…
The Heisenberg nearest neighbour antiferromagnet on the pyrochlore (3D) lattice is highly frustrated and does not order at low temperature where spin-spin correlations remain short ranged. Dzyaloshinsky-Moriya interactions (DMI) may be…
Spin-singlet orders are studied for the antiferromagnetic Heisenberg model with spin $S$>1/2 on a breathing pyrochlore lattice, where tetrahedron units are weakly coupled and exchange constants have two values $0<J' \ll J$. The ground state…
We present a certain class of two-dimensional frustrated quantum Heisenberg spin systems with multiple ring exchange interactions which are rigorously demonstrated to have quantum disordered ground states without magnetic long-range order.…
Classical Heisenberg model with both a nearest-neighbor antiferromagnetic interaction and long-range dipole-dipole interactions is investigated by numerically solving the Landau-Lifshitz (LL) equation. The ground state of the model without…
We investigate the phase diagram of the anisotropic spin-1/2 triangular lattice antiferromagnet, with interchain diagonal exchange J' much weaker than the intrachain exchange J. We find that fluctuations lead to a competition between…
The antiferromagnetic Heisenberg model on an anisotropic kagome lattice may be a good minimal model for real magnetic systems as well as a limit from which the isotropic case can be better understood. We therefore study the nearest-neighbor…
The Dzyaloshinskii-Moriya interaction (DMI) has explained successfully the weak ferromagnetism in {\it some} centrosymmetric antiferromagnets. However, in the last years, it was generally claimed that the DMI is not effective in such…
We study quantum antiferromagnets on two-dimensional bipartite lattices. We focus on local variations in the properties of the ordered phase which arise due to the presence of inequivalent sites or bonds in the lattice structure, using…
Motivated by the search for unconventional orders in frustrated quantum magnets, we present a multi-method investigation into the nature of the quantum phase diagram of the spin-$1/2$ Heisenberg model on the maple-leaf lattice with three…
Quasiperiodic structures possess long range positional order, but are freed of constraints imposed by translational invariance. For spins interacting via Heisenberg couplings, one may expect therefore to find novel magnetic configurations…
We study low-lying states of the XY and Heisenberg antiferromagnets on a triangular lattice to clarify whether spontaneous symmetry breaking occurs at $T=0$ in the thermodynamic limit. Approximate forms of low-lying states are proposed, in…
Magnetization and neutron diffraction measurements indicate long-range antiferromagnetic ordering below TN=4 K in the 2D, S=1/2 Heisenberg antiferromagnet K2V3O8. The ordered state exhibits ``weak ferromagnetism'' and novel, field-induced…
We study the classical Heisenberg model for spins on a pyrochlore lattice interacting via long range dipole-dipole forces and nearest neighbor exchange. Antiferromagnetic exchange alone is known not to induce ordering in this system. We…
We examine the influence of weak anisotropic interactions on the T=0 phase diagram of the frustrated two-leg Heisenberg ladder, a well-studied spin model exhibiting integer and fractional magnetization plateaux separated by gapless…
It is shown that the mechanism of order out of disorder is at work in the antisymmetric pyrochlore antiferromagnet. Quantum as well as thermal fluctuations break the continuous degeneracy of the classical ground state manifold and reduce…