Temperature-dependent carrier transport: Low-complexity model for the infrared optical and radiative properties of nickel

Abstract

We propose a framework for modeling the temperature-dependent infrared optical and radiative properties of metals exhibiting nonideal free-carrier dynamics. In order to do so, we derive a parsimonious model that possesses both multivariate (in temperature and wavelength) and single variate (in wavelength) components. The model is realized as the complex-valued relative permittivity, and is applicable to optically smooth media. A procedure is outlined for regressing both components of the model under an appropriate set of physical constraints that preclude superfluous degrees of freedom. The procedure is demonstrated by applying the model to nickel, a transition metal of technical significance that possesses nontrivial valency. The resulting model yields practically accurate results for eight data sets spanning four separate studies, representing the approximate wavelength (λ) bandwidth between 1 and 16 µm, and the approximate temperature (T) range between 0 and 1400 K. The proposed model framework retains phase information and can therefore be directly interfaced with more complex Fresnel frameworks, such as those commonly used for modeling systematically or randomly roughened surfaces.