Abstract
The Berezinskii-Kosterlitz-Thouless (BKT) phase transition in two-dimensional planar rotator and models on a square lattice, diluted by randomly placed vacancies, is studied here using hybrid Monte Carlo simulations that combine single spin flip, cluster, and over-relaxation techniques. The transition temperature is determined as a function of vacancy density by finite-size scaling of the helicity modulus and the in-plane magnetic susceptibility. The results for are consistent with those from the much less precise fourth-order cumulant of Binder. is found to decrease monotonically with increasing , and falls to zero close to the square lattice percolation limit, . The result is physically reasonable: the quasi-long-range orientational order of the low-temperature phase cannot be maintained in the absence of sufficient spin interactions across the lattice.
10 More- Received 23 March 2005
DOI:https://doi.org/10.1103/PhysRevB.72.094418
©2005 American Physical Society