Phase Diagram of Yukawa Systems: Model for Charge-Stabilized Colloids

The phase diagram of particles interacting through a repulsive screened Coulomb (Yukawa) potential has been calculated. Such interactions describe charge-stabilized colloidal suspensions and provide a potential of variable shape which can be used to test general ideas about phase transitions, including the phenomenological Hansen-Verlet and Lindemann rules. Competition between bcc and fcc solid phases was explored through calculations of the free-energy difference. For a range of screening lengths we found a transition from a low-temperature fcc phase to a high-temperature bcc phase.