Multiple control of thermoelectric dual‐function metamaterials

Diffusionics, distinct from traditional physical laws, focuses on designing material parameters to actively control diffusion fields. The introduction of transformation theory provides a novel method to achieve active control of diffusion transport, leading to the design of devices with unique functions such as cloaks, concentrators, and rotators. However, materials corresponding to the parameters designed by transformation theory are challenging to find in nature. Therefore, the spatial arrangement of one or multiple materials to effectively achieve the desired parameters has become an alternative approach, indirectly spurring the development of metamaterials. This article reviews the fundamental theories and theoretical framework in diffusion science. We first introduce the basic concept of transformation theory, followed by a review of alternative theories such as effective medium theory and scattering cancellation theory. To study topological phenomena in diffusion systems and space-time modulated systems, the foundations of quantum mechanics, namely matrix mechanics and wave mechanics, are employed. Lastly, the article summarizes some challenges in diffusion science theory, which may be addressed by other methods in the future, such as transformation field methods and machine learning approaches.

Diffusionics: Basic Theory and Theoretical Framework

Zhuang

2024

Radiative Metamaterials Based on Effective-Medium Theory

Tan,

2024

Thermal metamaterials have made significant advancements in the past few decades. However, the concept of thermal metamaterials is primarily rooted in the thermal conduction mechanism, which has consequently restricted their application scope. It is imperative to consider thermal radiation, another crucial thermal transport mechanism, particularly in high-temperature regimes, when designing thermal devices. In this chapter, we present the advancements in this area, with a specific focus on research conducted using the effective-medium theory. Additionally, we explore the potential applications of radiative thermal metamaterials and discuss prospective research directions from a microscopic perspective for future investigations.

Geometric Phases in Particle Diffusion with Non-Hermitian Hamiltonian Structures

Yang,

Huang

2024

Geometric phases in particle diffusion systems offer a different understanding beyond traditional Brownian motion and Fick’s laws. Here we introduce a unique structure composed of two rings moving in opposite directions and a stationary intermediate layer, which plays multifunctional roles in controlling particle diffusion. Numerical simulations using COMSOL Multiphysics validate the theoretical framework and provide deeper insights into the behavior of geometric phase. We also describe a bilayer particle-diffusion cloak, illustrating its simple design and adaptable control mechanisms. This system has potential applications in industries like healthcare and environmental management, thus expanding the understanding of the geometric phase and offering insights for the design of particle-diffusion metamaterials.