Lattice energies for crystals of colloidal spheroids

Attractive interactions between adjacent spheroids and excluded volume effects favor their parallel alignment. Parallel spheroids can be arranged into a variety of densely packed two-dimensional and three-dimensional lattice configurations. All of these configurations turn out to have the same lattice energy. A similar degeneracy is also found for several classes of lattices with lower volume density. We discuss implications of this degeneracy for the stability of colloidal crystals consisting of spheroids.