Interference in edge-scattering from monocrystalline gold flakes

TL;DR

This paper investigates how interference effects cause dissimilar light scattering at different edges of gold flakes, revealing insights into their structure and potential for material characterization.

Contribution

It uncovers the interference mechanism behind edge scattering differences in gold flakes, linking them to crystal symmetry and chirality, and proposes a method for material analysis.

Findings

Interference causes dissimilar scattering at gold flake edges.

Edge scattering differences relate to crystal symmetry and chirality.

Proposed method can estimate flake thickness and surface properties.

Abstract

We observe strongly dissimilar scattering from two types of edges in hexagonal quasi-monocrystalline gold flakes with thicknesses around 1 micron. We identify as the origin the interference between a direct, quasi-specular scattering and an indirect scattering process involving an intermediate surface-plasmon state. The dissimilarity between the two types of edges is a direct consequence of the three-fold symmetry around the [111]-axis and the intrinsic chirality of a face-centered cubic lattice. We propose that this effect can be used to estimate flake thickness, crystal morphology, and surface contamination.