Phase diagram of generalized fully frustrated XY model in two dimensions

Minnhagen, Petter; Kim, Beom Jun; Bernhardsson, Sebastian; Cristofano, Gerardo

Phase diagram of generalized fully frustrated XY model in two dimensions

Authors

Minnhagen, Petter

Kim, Beom Jun

Bernhardsson, Sebastian

Cristofano, Gerardo

Description

It is shown that the phase diagram of the two-dimensional generalized fully-frustrated XY model on a square lattice contains a crossing of the chirality transition and the Kosterlitz-Thouless (KT) transition, as well as a stable phase characterized by a finite helicity modulus $Υ$ and an unbroken chirality symmetry. The crossing point itself is consistent with a critical point without any jump in $Υ$, with the size ($L$) scaling $% Υ\sim L^{-0.63}$ and the critical index $ν\approx0.77$. The KT transition line remains continuous beyond the crossing but eventually turns into a first-order line. The results are established using Monte-Carlo simulations of the staggered magnetization, helicity modulus, and the fourth-order helicity modulus.
5 pages, 5 figures, in two columns