The antiferromagnetic xy model on the triangular lattice: topological singularities

Phase diagrams of the S = 12 quantum antiferromagnetic XY model on the triangular lattice in magnetic fields

1 2 quantum antiferromagnetic XY model on the triangular lattice in magnetic fields Abstract We study the S = 1 2 quantum antiferromagnetic XY model on finite triangular lattices with N sites in both longitudinal and transverse magnetic fields. We calculate physical quantities in the ground state using a diagonalization for spins N ≤ 27, and those at finite temperatures using a quantum transfer...

Critical behavior of the frustrated antiferromagnetic six-state clock model on a triangular lattice.

We study the antiferromagnetic six-state clock model with nearest neighbor interactions on a triangular lattice with extensive Monte Carlo simulations. We find clear indications of two phase transitions at two different temperatures: Below T(I) a chirality order sets in and by a thorough finite-size-scaling analysis of the specific heat and the chirality correlation length we show that this tra...

Order by disorder in the antiferromagnetic Ising model on an elastic triangular lattice.

Geometrically frustrated materials have a ground-state degeneracy that may be lifted by subtle effects, such as higher-order interactions causing small energetic preferences for ordered structures. Alternatively, ordering may result from entropic differences between configurations in an effect termed order by disorder. Motivated by recent experiments in a frustrated colloidal system in which or...

Fermi condensation near van Hove singularities within the Hubbard model on the triangular lattice.

The proximity of the Fermi surface to van Hove singularities drastically enhances interaction effects and leads to essentially new physics. In this work we address the formation of flat bands ("Fermi condensation") within the Hubbard model on the triangular lattice and provide a detailed analysis from an analytical and numerical perspective. To describe the effect we consider both weak-coupling...

Antiferromagnetic Heisenberg model on an anisotropic triangular lattice in the presence of a magnetic field