Monte Carlo study of a generalized-planar-model antiferromagnet with frustration

The phase transitions in a generalized $\mathrm{XY}$ model antiferromagnet on a two-dimensional triangular lattice are studied by means of Monte Carlo simulation. Small changes in the shape of the nearest-neighbor potential that have the property of preserving the symmetry of the Hamiltonian, give rise to a considerable range of transition temperatures. There appears to be always a single transition, simultaneously involving proliferation of domain walls and dissociation of vortex-antivortex pairs. This constitutes strong new evidence in favor of a recently suggested phase-transition scenario in the standard $\mathrm{XY}$ model.