Fluid of discs with competing interactions

We study within the framework of density functional theory the behaviour of a two-dimensional fluid with a competing attraction at short distances and repulsion at longer distance in addition to a hard core. The soft part of the interaction is treated by a first-order thermodynamic perturbation theory, which for a homogeneous bulk fluid predicts that thermodynamic quantities reduce to that of the hard-disc reference system. Despite this seemingly simple thermodynamic result, the behaviour of this fluid with competing interactions is rich and intriguing. In this work we follow the insight and inspirations by Reatto and co-workers, who performed computer simulation studies of the same system.