Au-Ag-Cu nano-alloys: tailoring of permittivity

TL;DR

This study systematically investigates how nanoscale alloying of Au, Ag, and Cu affects their permittivity, providing insights for designing materials with specific optical and plasmonic properties.

Contribution

It offers a comprehensive analysis of permittivity changes in Au-Ag-Cu alloys across various compositions using experimental and numerical methods.

Findings

Permittivity varies systematically with alloy composition.

Alloys exhibit face-centered cubic lattice structure.

Correlation established between structural parameters and optical properties.

Abstract

Precious metal alloys enables new possibilities to tailor materials for specific optical functions. Here we present a systematic study of the effects of a nanoscale alloying on the permittivity of Au-Ag-Cu metals at 38 different atomic mixing ratios. The permittivity was measured and analyzed numerically by applying the Drude model. X-ray diffraction (XRD) revealed the face centered cubic lattice of the alloys. Both, optical spectra and XRD results point towards an equivalent composition-dependent electron scattering behavior. Correlation between the fundamental structural parameters of alloys and the resulting optical properties is elucidated. Plasmonic properties of the Au-Ag-Cu alloy nanoparticles were investigated by numerical simulations. Guidelines for designing plasmonic response of nano- structures and their patterns are presented from the material science perspective.