arXiv:cond-mat/9507076 · Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics
Search for a Kosterlitz-Thouless transition in a triangular Ising antiferromagnet with further-neighbor ferromagnetic interactions
S. L. A. de Queiroz, Eytan Domany
Abstract
We investigate an antiferromagnetic triangular Ising model with anisotropic ferromagnetic interactions between further neighbors, originally proposed by Kitatani and Oguchi [J. Phys. Soc. Jpn. 57, 1344 (1988)]. The phase diagram as a function of temperature and the ratio between first- and second-neighbor interaction strengths is thoroughly examined. We search for a Kosterlitz-Thouless transition to a state with algebraic decay of correlations, calculating the correlation lengths on strips of width up to 15 sites by transfer-matrix methods. Phenomenological renormalization, conformal invariance arguments, the Roomany-Wyld approximation, and a direct analysis of the scaled mass gaps are used. Our results provide limited evidence that a Kosterlitz-Thouless phase is present. Alternative scenarios are discussed.