Low-density phase diagram of the two-dimensional Coulomb gas

Abstract

The phase diagram of the two-dimensional classical Coulomb gas is investigated by Monte Carlo simulations. We show that in the fluid phase this system undergoes the expected Kosterlitz-Thouless transition at very low densities and that the Kosterlitz-Thouless transition becomes a first-order phase transition between a dielectric gas and a conductive liquid at moderate densities. We give an estimate of the location of the critical point of this first-order transition.