Microscopic model for magnetoelectric coupling through lattice distortions

We propose a microscopic magnetoelectric 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 electri...

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Bibliographic Details
Published in:Physical review. B 2019-10, Vol.100 (16), Article 161111
Main Authors: Cabra, D. C., Dobry, A. O., Gazza, C. J., Rossini, G. L.
Format: Article
Language:English
Subjects:
Computer simulation
Coupling
Deformation effects
Distortion
Electric dipoles
Electric fields
Heisenberg theory
Ising model
Magnetic sectors
One dimensional models
Solitary waves
Statistical models
Two dimensional models
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Summary:We propose a microscopic magnetoelectric 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 magnetoelectric coupling which arises due to the interconnecting lattice deformations is quite efficient in one-dimensional arrays. More precisely, we show using bosonization and extensive density matrix renormalization group 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 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.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.100.161111