Phase Behavior and Structure of Binary Hard-Sphere Mixtures

Abstract

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 $q\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.1$. For $q\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.05$ the solid-solid coexistence becomes stable.