Hall Transport of Charged Particles in Magnetic Disk Array

TL;DR

This paper introduces metafields, a novel concept of dynamic magnetic field patterns, and investigates charged particle Hall transport in magnetic disk arrays, revealing directional diffusion effects.

Contribution

It proposes metafields as a new way to control particle dynamics dynamically, and analyzes Hall transport phenomena in magnetic disk arrays using theoretical methods.

Findings

Directional diffusion at interfaces between opposing field arrays

Transport coefficients depend on magnetic field configurations

Potential for dynamic particle manipulation applications

Abstract

The concept of periodic structures has driven the development of advanced materials like photonic and phononic crystals. These metamaterials typically rely on complex repeating units or meta-atoms, limiting their adaptability after fabrication. To overcome this limitation, we introduce the concept of metafields, which are repeating patterns of local magnetic fields instead of material structures. Unlike metamaterials, which consist of atoms arranged in structured patterns, metafields focus on the patterns of fields alone, allowing for dynamic property adjustments through external electric currents. This study explores a specific metafield where the repeating pattern is the magnetic disk (MD), defined by a uniform magnetic field perpendicular to its surface. By arranging multiple MDs, we form a magnetic disk array (MDA) and theoretically investigate the charged particle dynamics within this array. Our analysis highlights Hall transport phenomena, such as Hall diffusivity, conductivity, and thermal Hall effects. Using complex variables, we derive the collision integral and Boltzmann equation for particle distribution, applying perturbation methods and Fourier analysis to calculate transport coefficients. Simulations reveal a one-way preferential diffusion at the interface between MDAs with opposing field directions, where diffusion intensity varies with the particle movement direction. This highlights metafields' potential for dynamic particle control applications.