On the continuity of the magnetization and energy in Ising ferromagnets

Abstract

The authors investigate the phase diagram of ferromagnetic Ising spin systems satisfying the G.H.S. inequality. They show that such systems cannot have a ''normal'' first-order phase transition as the temperature T is varied, i.e., one where the magnetization is discontinuous and there are three coexisting phases. Furthermore, for N.N. interactions, discontinuity in the magnetization at 0 < T/sub 0/ less than or equal to T/sub c/ implies an uncountable infinity of pure phases at T/sub 0/.