Low-temperature analysis of three-phase coexistence

We study the properties of an isotropic lattice model by low-temperature expansion. In particular, the interface between ferromagnetic phases for the case when a third modulated phase is in thermodynamic equilibrium is considered. Throughout the three-phase coexistence region the interfacial tension between all three phases is very low and actually vanishes at zero temperature. This reflects the fact that the surface of the finite-temperature three-phase equilibria arises from a curve of zero-temperature multiphase points. We show that throughout the three-phase region and in the limit of low temperature, the modulated phase never wets the interface between the ferromagnetic phases.