Phase behavior of hard spheres with a short-range Yukawa attraction.

The phase diagram of a system consisting of hard spheres with an attractive Yukawa interaction is computed by Monte Carlo simulations. Upon decreasing the range of attraction, we find the following scenarios: (a) a stable fluid-fluid and fluid-solid transition, a triple point with fluid-fluid-solid coexistence, and a metastable isostructural solid-solid transition (b) a fluid-fluid and isostructural solid-solid transition, which are both metastable with respect to a broad fluid-solid transition, (c) a metastable fluid-fluid transition, a stable isostructural solid-solid and fluid-solid transition and a triple point with fluid-solid-solid coexistence. Our results show that a large part of the fluid-solid coexistence region is occupied by metastable fluid-fluid and/or solid-solid coexistence regions, which has repercussions on the kinetics and on the nonequilibrium behavior of the system, such as nucleation, vitrification, and gelation.