Triangular Lattice In Presence Research Articles

Case study of the uniaxial anisotropic spin-1 bilinear-biquadratic Heisenberg model on a triangular lattice

We study the spin-$1$ model in a triangular lattice in presence of a uniaxial anisotropy field using a Cluster Mean-Field approach (CMF). The interplay between antiferromagnetic exchange, lattice geometry and anisotropy forces Gutzwiller mean-field approaches to fail in a certain region of the phase diagram. There, the CMF yields two supersolid (SS) phases compatible with those present in the spin-$1/2$ XXZ model onto which the spin-$1$ system maps. Between these two SS phases, the three-sublattice order is broken and the results of the CMF depend heavily on the geometry and size of the cluster. We discuss the possible presence of a spin liquid in this region.

Collective surface diffusion on a triangular lattice in presence of ordered phases

Diffusion is studied in a two-dimensional gas of triangular symmetry with repulsive interactions. The collective diffusion coefficient, D c, is calculated as the ratio of the average jump rate and the zero-wave-vector static structure factor (Darken approximation). The dependence of D c on coverage, θ, is studied in both the disordered and ordered regions of the phase diagram. It is shown that, around the coverages of the perfect ordered phases ( θ=1/3 and 2/3), D c changes of orders of magnitude in tiny θ ranges.