Analysis of Electromagnetic Scattering from Semiconductor Nanostructures by Solving Coupled Volume Integral and Two-fluid Hydrodynamic Equations

TL;DR

This paper introduces a volume integral equation solver coupled with a two-fluid hydrodynamic model to analyze electromagnetic scattering in semiconductor nanostructures, capturing unique plasmonic phenomena more accurately.

Contribution

It presents a novel VIE-based approach that couples the electric flux density with two-fluid polarization currents, enabling efficient and accurate analysis of semiconductor nanostructures.

Findings

The method accurately captures acoustic plasmon resonances.

It demonstrates the ability to model blueshift in localized surface plasmon resonances.

The approach is more efficient than finite-element methods for these problems.

Abstract

Semiconductor-based plasmonic nanostructures support localized surface plasmon modes in the infrared region. Unlike metallic nanostructures, they support both free electrons and holes, requiring a two-fluid hydrodynamic Drude equation (HDE) to accurately capture spatial dispersion effects and low-frequency acoustic plasmon modes that cannot be described by single-fluid models. In this work, a volume integral equation (VIE)-based solver is proposed for the analysis of electromagnetic scattering from semiconductor nanostructures. The proposed approach couples the VIE, formulated in terms of the electric flux density and the free-electron and hole polarization currents, with the two-fluid HDE. The coupled system is discretized using a tetrahedral mesh and solved efficiently using a two-level iterative solver. In contrast to finite-element-based methods, the proposed VIE-based approach does not require domain-wide meshing and inherently satisfies the radiation condition, thereby eliminating artificial absorbing boundaries. Numerical results for InSb-type semiconductor nanostructures demonstrate the accuracy and efficiency of the proposed VIE-based solver and its ability to capture unique optical phenomena, such as acoustic plasmon resonances and the blueshift of localized surface plasmon resonances, that cannot be described by the single-fluid HDE or classical Drude-based models.