  The crystal-melt interfaces of a binary hard-sphere fluid mixture in
coexistence with a single-component hard-sphere crystal is investigated using
molecular-dynamics simulation. In the system under study, the fluid phase
consists of a two-component mixture of hard spheres of differing size, with a
size ratio $\alpha=0.414$. At low pressures this fluid coexists with a pure fcc
crystal of the larger particles in which the small particles are immiscible.
For two interfacial orientations, [100] and [111], the structure and dynamics
within the interfacial region is studied and compared with previous simulations
on single component hard-sphere interfaces. Among a variety of novel
properties, it is observed that as the interface is traversed from fluid to
crystal the diffusion constant of the larger particle vanishes before that of
the small particle defining a region of the interface where the large particles
are frozen in their crystal lattice, but the small particles exhibit
significant mobility. This behavior was not seen in previous binary hard-sphere
interface simulations with less asymmetric diameters.
