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We report a method based on density functional theory molecular dynamics that allows us to calculate the plasmonic properties of liquid metals and metal alloys from first principles with no a priori knowledge of the system. We show exceptional agreement between the simulated and measured optical constants of liquid Ga and the room temperature liquid In–Ga eutectic alloy (Tm = 289 K). We then use this method to analyze the plasmonic properties of various alloy concentrations in the In–Ga system. The plasmonic performance of the In–Ga system decreases with increasing In concentration. However, the benefits of a room-temperature plasmonic liquid are likely to outweigh the minor reduction in plasmonic performance when moving from pure Ga to the eutectic composition. Our results show that density functional theory molecular dynamics can be used as a predictive tool for studying the optical properties of liquid metal systems amenable to plasmonics. [ABSTRACT FROM AUTHOR]

We utilize a peptide-based methodology to prepare a diverse collection of double-helical gold nanoparticle superstructures having controllable handedness and structural metrics. These materials exhibit well-defined circular dichroism signatures at visible wavelengths owing to the collective dipole-dipole interactions between the nanoparticles. We couple theory and experiment to show how tuning the metrics and structure of the helices results in predictable and tailorable chirooptical properties. Finally, we experimentally and theoretically demonstrate that the intensity, position, and nature of the chirooptical activity can be carefully adjusted via silver overgrowth. These studies illustrate the utility of peptide-based nanoparticle assembly platforms for designing and preparing complex plasmonic materials with tailorable optical properties.

This paper reports the manipulation of surface plasmon polaritons (SPPs) in a liquid plasmonic metal by changing its physical phase. Dynamic properties were controlled by solid-to-liquid phase transitions in 1D Ga gratings that were fabricated using a simple molding process. Solid and liquid phases were found to exhibit different plasmonic properties, where light coupled to SPPs more efficiently in the liquid phase. We exploited the supercooling characteristics of Ga to access plasmonic properties associated with the liquid phase over a wider temperature range (up to 30 °C below the melting point of bulk Ga). Ab initio density functional theory-molecular dynamic calculations showed that the broadening of the solid-state electronic band structure was responsible for the superior plasmonic properties of the liquid metal.