DFT-Based Approach Enables Deliberate Tuning of Alloy Nanostructures Plasmonic Properties

Using DFT we calculated band structures and dielectric functions of multiple binary alloy systems. The obtained data enabled us to elucidate the interconnection between alloy composition, fundamental properties such as band structure and their optical properties. The analysis provides the explanation for the smooth change of optical properties in the UV/VIS range and reveals the appearance of strong optical losses in the IR range due to interband transitions. Since they are present in all alloys but not in pure metals we identify such transitions as an emergent property of alloying. To predict plasmonic properties of different alloy nanostructures we performed electrodynamics simulations based on calculated and experimental dielectric functions. The results showed that that calculations based on the standardly used PBE functional in some cases drastically deviate from experiment-based results, and the calculations with an equally efficient GLLB-SC functional are superior.