English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

The behavior of nanoscale infrared antenna elements depends upon the dynamic conductivity of thin metallic films. Spectroscopic ellipsometer measurements of noble metal films show that when the product of the incident radiation frequency and the relaxation time is greater than unity, anomalous dynamic electron transport effects occur. In this regime electron scattering increases the conductivity of alloyed metallic films as demonstrated by ellipsometry measurements of films from the Au-Cu system. A binary alloy thin film was fabricated with equal parts of Au and Cu, and the dynamic conductivity was measured to be 300% larger than the high frequency conductivity of pure Au or pure Cu films at wavelengths in the 3-5 m band. When electronic scattering is reduced, ellipsometer measurements of Au and Cu films taken near 4 K demonstrate that the IR conductivity decreases to 20% of the value measured at 300 K at wavelengths in the 3-5 m band. Using measured dc relaxation times, a model to explain deviations from Drude behavior was developed using the theory of the anomalous skin effect and frequency dependent relaxation time. This model was in quantitative agreement with the measured data. The ability to design an alloyed metallic thin film using a calculated ideal dc relaxation time to produce the greatest possible dynamic conductivity for infrared antennas and metamaterials was demonstrated. © 2008 American Institute of Physics. DOI: 10.1063/1.3026717 I. INTRODUCTION The dynamic conductivity describes the propagation of a current wave on a metallic structure in response to incident electromagnetic radiation. As derived from the Drude model, dynamic conductivity is a complex number with the real part corresponding to Ohmic loss and the imaginary term corre- sponding to the permittivity of the metal. The permittivity is an important material property for near field surface plasmon resonance, but it has less impact on the behavior of antenna systems. Within the semiclassical framework considered in this paper, and limiting the discussion to polycrystalline met- als, dynamic conductivity is a scalar quantity given in Eq. 1 below where j is the current density, E is electric field, and is dynamic conductivity. j = E. 1

Relaxation time effects on dynamic conductivity of alloyed metallic thin films in the infrared band