Self-Assembly of Colloidal Diamond from Soft Compressible Colloids with Tetrahedrally Anisotropic Interaction

The self-assembly of colloidal particles into a colloidal diamond structure is an intriguing process with potential applications in photonic materials, metamaterials, and other advanced materials. Indeed, the self-assembly of colloidal diamond remains a challenge due to the complexity of the process and the precise control required over various factors. In this study, we demonstrate the spontaneous formation of diamond-like lattices from soft, compressible colloids with tetrahedrally anisotropic interactions. The particles' softness allows for overlapping, enabling a maximizing packing efficiency, while anisotropic interactions promote selective bonding crucial for the diamond lattice formation. Our calculations of the photonic band structure demonstrate that the resulting lattices (both inverse and direct lattice) exhibit a three-dimensional complete photonic bandgap. Notably, the inverse lattice configuration achieves a maximum bandgap of approximately 34%.