Competing nematic interactions in a generalized XY model in two and three dimensions.

We study a generalization of the XY model with an additional nematic-like term through extensive numerical simulations and finite-size techniques, both in two and three dimensions. While the original model favors local alignment, the extra term induces angles of 2π/q between neighboring spins. We focus here on the q=8 case (while presenting new results for other values of q as well) whose phase diagram is much richer than the well-known q=2 case.

Kosterlitz-Thouless and Potts transitions in a generalized XY model.

We present extensive numerical simulations of a generalized XY model with nematic-like terms recently proposed by Poderoso et al. [ Phys. Rev.