Refraction Indices of Non-Uniform Systems from the First Principles
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1223-EE03-12
Refraction Indices of Non-Uniform Systems from the First Principles Liudmila A. Pozhar1 1
University of Idaho, Department of Physics, P.O. Box 440903, Moscow, ID 83844, U.S.A.
ABSTRACT A novel, first-principle theoretical approach and synergetic computational methods designed to predict electronic and magnetic transport properties of strongly spatially inhomogeneous systems, including small quantum dots and wires (QDs and QWs, respectively), and molecules, have been developed recently. This approach is based on a many-body quantum theoretical formalism - a projection operator method due to Zubarev and Tserkovnikov (ZT) – formulated in terms of the equilibrium, two-time temperature Green functions (or TTGFs). There are several significant advantages of this approach, as compared to traditional non-equilibrium two-time thermodynamic and field-theoretical Green’s function (NGF) methods that are currently used to study electronic and magnetic transport properties of strongly spatially inhomogeneous systems. In particular, the TTGFs are directly related to experimentally assessable microscopic charge, spin and microcurrent densities. In the work reported here the TTGF-based approach has been used to derive a fundamental, yet tractable expression for the space-time Fourier transform of the tensor of quasi-local refraction indices (TRI) from the first principles. The TTGFs necessary to predict TRI can be calculated using quantum statistical mechanical means, modeling and simulations, and experimental data. Applications of the theoretical predictions for TRI open new prospects in materials design. In particular, the derived theoretical expression for TRI can be used to guide experimental synthesis of structured materials and systems with both direction- and positiondependent indices of refraction in desirable frequency ranges.
INTRODUCTION In recent years, a remarkable progress in experimental materials synthesis has given rise to almost an exponential increase in publications concerning refraction indices of strongly spatially inhomogeneous materials and systems, and in particular those of nanostructured materials, composites and metamaterials. Such systems can be engineered to realize the indices of refraction with some specific properties, including the negative index of refraction (NIR) [1,2]. One of the most important properties of NIR materials for applications in device development is that the surface of such a material can support plasmon polaritons coupled to short-lived evanescent waves that carry information on subwavelength details of an object. Propagation of such evanescent waves in a NIR material can be largely enhanced using resonant plasmon polaritons, thus providing a means to produce images with sub-wavelength resolution [3,4]. A number of NIR systems have been realized experimentally, including metamaterials with NIR in
microwave frequency range [4-7]. Recently, analysis of terahertz reflection from a metamaterial composed of a monolayer of nanosize resonators indicated that three-dime
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