Do the Tellegen particles really exist in electromagnetics?

TL;DR

This paper critically examines the existence of Tellegen particles in electromagnetics, proposing that magnetoelectric particles with unique symmetry properties, such as ferrite disks with magnetic-dipolar-mode oscillations, are the physical basis for magnetoelectric effects.

Contribution

The paper challenges the traditional concept of Tellegen particles and introduces magnetoelectric particles with specific symmetry features as the physical entities responsible for magnetoelectric phenomena.

Findings

Elementary symmetry analysis questions the simple combination of electric and magnetic dipoles.

Classical models and near-field structures do not support local junctions of electrical and magnetic properties.

Ferrite disks with magnetic-dipolar-mode oscillations exhibit unique symmetry and topological phases leading to magnetoelectric properties.

Abstract

In 1948 Tellegen suggested that an assembly of the lined up electric-magnetic dipole twins can construct a new type of an electromagnetic material. Till now, however, the problem of creation of the Tellegen medium is a subject of strong discussions. An elementary symmetry analysis makes questionable an idea of a simple combination of two (electric and magnetic) dipoles to realize local materials with the Tellegen particles as structural elements. In this paper we show that in his search of sources with local junctions of the electrical and magnetic properties one cannot rely on the induced parameters of small electromagnetic scatterers. No near-field electromagnetic structures and classical motion equations for point charges give a physical basis to realize sources with the local junction of the electrical and magnetic properties. We advance a hypothesis that local magnetoelectric (ME) particles should be the physical objects with eigenmode oscillation spectra and non-classical symmetry breaking effects. Our studies convincingly prove this assumption. We show that a quasi-2D ferrite disk with magnetic-dipolar-mode oscillations is characterized by unique symmetry features with topological phases resulting in appearance of the ME properties. The entire ferrite disk can be characterized as a combined system with eigen electric and magnetic moments. The fields near such a particle are distinguished by special symmetry properties.