The critical curve for the quenched dilute random-bond Ising model

Abstract

The treatment by Frank and Barnea of the quenched dilute random-bond model for a system of Ising spins is improved by means of a more self-consistent calculation. This is done by relaxing one of their assumptions, which is replaced by an as yet unexploited identification, noted by Frank and Jan, with the coherent potential – random phase approximation formulation of Tahir-Kheli and Elliott. The results for the critical temperature as a function of the concentration of connected bonds are consequently better in relation to Rapaport's series values. However, at very low concentrations [Formula: see text], the theory remains inadequate.