Interfacial effect on effective dielectric response of spherical granular composites

The interfacial effect on effective dielectric response of a granular composite, in which spherical particles with graded and step-like graded interfaces are randomly embedded in a host matrix, is investigated. Based on a first-principle approach, we derived the effective dielectric constant of the composite with graded interfaces in a dilute limit. The approach has been applied to power-law dielectric gradation profile in interfaces and the exact result is available. The general expression of effective dielectric constant in the composite with step-like graded interfaces is also obtained. Comparing the results for graded and step-like graded interfaces with those obtained for sharp interfaces, we found that the interfacial conditions have a great effect on the effective dielectric response. The graded interfaces are favor to widen the absorption spectrum, to control surface plasma resonance and to reduce the fluctuations of effective dielectric constant