Routes to left-handed materials by magnetoelectric couplings

Magnetoelectric materials, which couple electric fields with magnetic fields, are intensively studied for physical realization and potential synthesis of left-handed materials (LHM). Both isotropic and anisotropic magnetoelectric materials are the realization of backward waves and/or negative refraction within certain frequency bands. Since the magnetoelectric coupling (scalar or tensorial) parameters may significantly reduce the refractive indices and even cause the anisotropic nihility, left-handed materials can be realized without requiring the resonances of the permittivity and permeability. Wave-field theorem is thus applied to obtain the effective parameters in their equivalent isotropic counterparts, and dispersion models associated with mixing rules are considered as an alternative important factor to achieve LHM.