Optical properties of a disordered metallic film: local vs. collective phenomena

TL;DR

This paper investigates the optical response of disordered metallic films with dipole interactions, highlighting the importance of nonlocal effects and comparing dual-variable and cluster approaches for modeling spatial correlations.

Contribution

It introduces a dual-variables approach to better account for long-range correlations in the optical properties of disordered metallic films.

Findings

Long-range dipole interactions significantly influence optical response.

Dual-variables method improves upon coherent-potential approximation.

Short-range correlations affect spectral properties, long-range correlations impact k-dependence.

Abstract

We apply the dual-varibles approach to the problem of the optical response of an disordered film of metal particles with dipole-dipole interaction. Long range dipole-dipole interaction makes the effect of spatial correlations significant, so that dual-variables technique provides a desirable improvement of the coherent-potential results. It is shown that the effect of nonlocality is more pronounced for a medium-range concentration of the particles. The result is compared with the non-local cluster approach. It is shown that short-range correlations accounted in the cluster method reveal themselves in the spectral properties of the response, whereas long-range phenomena kept in the dual technique are more pronounced in the k-dependence of the Green's function.