Double frustration and magneto-electro-elastic excitations in collinear multiferroic materials

TL;DR

This paper explores complex magneto-electric-elastic excitations in collinear multiferroic materials, revealing how magnetic frustration and external fields induce composite quasiparticles with potential experimental signatures.

Contribution

It introduces a model for type II multiferroics showing how magnetic frustration and fields produce unique magneto-electric-elastic quasiparticles, supported by DMRG and self-consistent calculations.

Findings

Quantum magnetic plateau states emerge due to frustration.

Composite excitations involve fractionalized spins and dipolar domain walls.

Enhanced elastic distortions are linked to magneto-electric effects.

Abstract

We discuss a model scenario for multiferroic systems of type II (collinear spins) where the electric dipolar order competes with a frustrated magnetic order in determining the elastic distortions of the lattice ion positions. High magnetic frustration due to second neighbors exchange and small spin easy-axis anisotropy lead to the appearance of the so called quantum magnetic plateau states. Increasing the magnetic field above the plateau border produces composite excitations, where fractionalized spin tertions arise together with spontaneous dipolar flips (in the form of domain walls) and enhanced localized elastic distortions. This peculiar magneto-electric effect may be described by magneto-electric-elastic (MEE) quasiparticles that could be detected by X-ray and neutron diffraction techniques. Our results are supported by extensive DMRG computations on the spin sector and self-consistent equations for the lattice distortions.