Metal-insulator nanocomposites which act optically like homogeneous conductors

• Main Authors: Smith, Geoffrey B., Gentle, Angus R., Maaroof, Abbas I.
• Format: text
• Published: Animo Repository 2007
• Subjects: Gold—Surfaces—Optical properties; Mesoporous materials—Surfaces—Optical properties; Surface plasmon resonance; Physics
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/8177
• Institution: De La Salle University

Conductor-insulator nanocomposites in which the conductor percolates can have optical responses at longer wavelengths like dense conductors with an effective plasma frequency omega(*)(p). This applies at wavelengths where the Bergman spectral function F for permittivity varies sufficiently slowly with wavelength omega(*)(p) can be engineered by varying the components, the nanostructure's topology, or the dielectric volume fraction f. The homogenized conductor acts like a dense conductor whose charge carriers have effective mass m(eff)(*). Results are presented for omega(*)(p)(f) and m(eff)(*)(f) using the Maxwell Garnett (MG) and Bruggeman (BR) models for spheres and aligned ellipsoids. In the BR case m(eff)(*)(f) at the percolation concentration is singular. Example omega(*)(p) data for spheres and ellipsoids are given which match predictions. Anisotropy in effective mass is considered, such that effective plasma frequency can depend strongly on polarization direction of incident light.