Numerical Simulation of Spin-Chirality Switching in Multiferroics via Intense Electromagnon Excitations

TL;DR

This paper demonstrates theoretically that intense terahertz electromagnetic pulses can switch the spin chirality in multiferroic TbMnO3 by exciting electromagnons, enabling ultrafast electric control of magnetic states.

Contribution

It introduces a detailed spin Hamiltonian model showing how picosecond optical pulses can switch spin chirality via electromagnon excitation in multiferroics.

Findings

Picosecond optical pulses can switch spin chirality.

Electromagnon excitation enables ultrafast control.

Theoretical model accurately describes the process.

Abstract

Chirality, i.e., the right- and left-handedness of structure, is one of the key concepts in many fields of science including biology, chemistry and physics, and its manipulation is an issue of vital importance. The electron spins in solids can form chiral configurations. In perovskite manganites RMnO3 (R=Tb, Dy,...etc), the Mn-spins form a cycloidal structure, which induces ferroelectric polarization (P) through the relativistic spin-orbit interaction. This magnetism-induced ferroelectricity (multiferroics) and associated infrared-active spin waves (electromagnons) open a promising route to control the spins by purely electric means in a very short time. In this paper, we show theoretically with an accurate spin Hamiltonian for TbMnO3 that a picosecond optical pulse can switch the spin chirality by intensely exciting the electromagnons with a terahertz frequency.