The commensurate-disordered phase transition in the 2D classical ATNNI model studied by DMRG

The classical two-dimensional anisotropic triangular nearest-neighbour Ising (ATNNI) model is studied by the density matrix renormalization group (DMRG) technique when periodic boundary conditions are imposed. Applying the finite-size scaling to the DMRG results, a commensurate-disordered (CD) phase transition line as well as temperature and magnetic critical exponents are calculated. We conclude that the CD phase transition in the ATNNI model belongs to the same universality class as the ordered-disordered phase transition of the Ising model.