Phase Behavior and Structure of Binary Hard-Sphere Mixtures

By integrating out the degrees of freedom of the small spheres in a binary mixture of large and small hard spheres, we derive an explicit effective Hamiltonian for the large spheres. Using the two-body (depletion potential) contribution to this effective Hamiltonian in simulations, we find stable fluid-solid and both metastable fluid-fluid and solid-solid coexistence in a mixture with size ratio $q=0.1\mathrm{}$. For $q=0.05\mathrm{}$ the solid-solid coexistence becomes stable.