A Frustrated Antiferromagnetic Ising Model on the Hexagonal Lattice

Abstract

An antiferromagnetic Ising model on the hexagonal lattice with intra- and inter-layer nearest neighbor interactions is carefully studied by using a Monte Carlo method. It is shown that a fluctuating phase called a randomly modulated phase (RMP) occurs at all temperatures below a Neel temperature in contrary to results by Blankschtein et al. In this phase, a correlation function of two spins decays in a power law of r -η with \(\eta{\gtrsim}1\). Similarity between our model and an XY model with a six-fold anisotropy energy is discussed in detail.