Physical review. B, Condensed matter
Finite-lattice calculations for the two-dimensional axial-next-nearest-neighbor Ising model
Gareth O. Williams, Pál Ruján, H. L. Frisch
Abstract
The two-dimensional axial-next-nearest-neighbor Ising model is studied numerically using finite-lattice results. The row-to-row transfer matrix is mapped into a simple one-dimensional spin-$\frac{1}{2}$ quantum Hamiltonian. The leading eigenvalues and the corresponding eigenvectors are calculated numerically for chains of finite lengths. Using a finite-lattice renormalization-group transformation the high- (low-) temperature region is analyzed with the use of the Hamiltonian for the original (dual) model. Although there is no clear evidence for a massless phase, the phase boundaries obtained in this way are a strong indication of the presence of a sinusoidal phase between the paramagnetic and the $〈2〉$ antiphase, in fair agreement with previous analytical results.