Physical Review Letters
Griffiths singularities in two-dimensional random-bond Ising models: Relation with Lifshitz band tails
Theo M. Nieuwenhuizen
Abstract
Ising models with correlated or uncorrelated random horizontal bonds are studied for square lattices in zero field. The partition sum is expressed in terms of a one-component field. Griffiths singularities in the free energy as function of temperature are derived. They are log-transforms of certain Lifshitz band tails. Griffiths singularities occur above as well as below the critical temperature.