Orientational order in two dimensions from competing interactions at different scales

We discuss orientational order in two dimensions in the context of systems with competing isotropic interactions at different scales. We consider an extension of the Brazovskii model for stripe phases including explicitly quartic terms with nematic symmetry in the energy. We show that leading fluctuations of the mean field nematic solution drive the isotropic-nematic transition into the Kosterlitz-Thouless universality class, i.e. these systems have a thermodynamic phase with orientational quasi-long-range order.