Reentrance Phenomena in the Two-Dimensional XY Spin Glass

A Monte Carlo study is made on the two-dimensional ± J plane-rotator ( X Y ) model on the square lattice in the ferromagnet-rich region. Reentrance phenomena are observed with the intermediate quasi-ferromagnetic and the low-temperature chiral spin glass states. It is found that the reentrant spin glass state is characterized with the existence of frozen-in vortices.