Phase diagram for the generalized Villain model.
Academic Article
Overview
Identity
Additional Document Info
Other
View All
Overview
abstract
Berge et al. have generalized Villains fully frustrated XY model on a square lattice by multiplying the antiferromagnetic exchange constant by a factor. Using the Monte Carlo method, they find that the specific heat displays both Ising-type and Kosterlitz-Thouless-type phase transitions with TI1 is found to possess antiferromagnetic order. When a magnetic field H is included, the paramagnetic and ferromagnetic phases coalesce to a single collinear phase, and the antiferromagnetic and noncollinear phases coalesce to a single noncollinear phase. The critical surface Hc(T,) separating these phases (which should be characterized by a divergence in the staggered susceptibility) has been determined, again within mean-field theory. A phase-only mode-fluctuation analysis is also presented, yielding results consistent with the mean-field analysis, as well as explicitly revealing the fluctuating modes that become unstable at the transitions; with these modes one can explain the presence (and absence) of susceptibility peaks for the four phase transitions found by Berge et al. For TI