If you can uniformly break the symmetry of nanorod pairs in a colloidal solution, you’re one step closer to achieving new and exciting metamaterial properties. The development of an innovative self-assembly route could surpass the conventional thermodynamic limit in chemical synthetic systems and lead to the production of nanostructures that have historically been considered impossible to assemble. But traditional thermodynamic-driven colloidal assembly of these metamaterials, which are materials defined by their non-naturally-occurring properties, often result in structures with a high degree of symmetries in the bulk material. In this case, the energy requirement does not allow the structure to break its symmetry.
Utilizing the Molecular Foundry through a user project, Xiang Zhang and his research group at the UC Berkeley achieved symmetry-breaking in a bulk metamaterial solution for the first time. The team demonstrated self-assembled optical metamaterials with tailored broken-symmetries and hence unique electromagnetic responses that can be achieved via their new method.