Absence of Reentrance in the Two-Dimensional XY-Model with Random Phase Shift
Abstract
We show that the 2D XY-model with random phase shifts exhibits for low temperature and small disorder a phase with quasi-long-range order, and that the transition to the disordered phase is not reentrant. These results are obtained by heuristic arguments, an analytical renormalization group calculation, and a numerical Migdal-Kadanoff renormalization group treatment. Previous predictions of reentrance are found to fail due to an overestimation of the vortex pair density as a consequence of the independent dipole approximation. At positions where vortex pairs are energetically favored by disorder, their statistics becomes effectively fermionic. The results may have implications for a large number of related models.
- Publication:
-
Journal de Physique I
- Pub Date:
- May 1995
- DOI:
- 10.1051/jp1:1995152
- arXiv:
- arXiv:cond-mat/9501120
- Bibcode:
- 1995JPhy1...5..565N
- Keywords:
-
- Condensed Matter
- E-Print:
- 5 pages, latex, with 2 figures, one author added, minor text changes, to be published in J. de Physique I