# Microscopic model for magneto-electric coupling through lattice distortions

## TL;DR

This paper introduces a microscopic model linking magnetism and electric polarization via lattice distortions, demonstrating efficient magneto-electric coupling and electric control of magnetization in one-dimensional systems.

## Contribution

It presents a novel microscopic magneto-electric model incorporating lattice distortions, spin, and electric dipoles, with detailed analysis using bosonization and DMRG simulations.

## Key findings

- Magneto-electric coupling is highly effective in 1D arrays.
- Magnetic field can switch polarization by creating soliton pairs.
- Electric fields can control magnetization states in gapped phases.

## Abstract

We propose a microscopic magneto-electric model in which the coupling between spins and electric dipoles is mediated by lattice distortions. The magnetic sector is described by a spin S=1/2 Heisenberg model coupled directly to the lattice via a standard spin-Peierls term and indirectly to the electric dipole variables via the distortion of the surrounding electronic clouds. Electric dipoles are described by Ising variables for simplicity. We show that the effective magneto-electric coupling which arises due to the interconnecting lattice deformations is quite efficient in one-dimensional arrays. More precisely, we show using bosonization and extensive DMRG numerical simulations that increasing the magnetic field above the spin Peierls gap, a massive polarization switch-off occurs due to the proliferation of soliton pairs. We also analyze the effect of an external electric field $E$ when the magnetic system is in a gapped (plateau) phase and show that the magnetization can be electrically switched between clearly distinct values. More general quasi-one-dimensional models and two-dimensional systems are also discussed.