title: Topological Aspects of Symmetry Breaking in Triangular-Lattice Ising Antiferromagnets.
abstract: Using a specially designed Monte Carlo algorithm with directed loops, we investigate the triangular lattice Ising antiferromagnet with coupling beyond the nearest neighbors. We show that the first-order transition from the stripe state to the paramagnet can be split, giving rise to an intermediate nematic phase in which algebraic correlations coexist with a broken symmetry. Furthermore, we demonstrate the emergence of several properties of a more topological nature such as fractional edge excitations in the stripe state, the proliferation of double domain walls in the nematic phase, and the Kasteleyn transition between them. Experimental implications are briefly discussed.
authors.affiliation: Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Andrew
authors.initials: A
authors.lastname: Smerald
authors.affiliation: L. D. Landau Institute for Theoretical Physics, Kosygina 2, Moscow 119334, Russia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Korshunov
authors.affiliation: Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Mila