Light-induced switching of magnetic order in the anisotropic triangular-lattice Hubbard model

TL;DR

This study uses time-dependent exact diagonalization to show that high-frequency light fields can switch magnetic orders in the anisotropic triangular-lattice Hubbard model, demonstrating controllability of magnetic phases.

Contribution

It introduces a method to control magnetic order transitions via high-frequency periodic fields, supported by Floquet theory and effective Hamiltonian analysis.

Findings

High-frequency fields induce transition from 120° to Néel order.

Effective Heisenberg Hamiltonian accurately describes the system.

Magnetic order depends on the ratio of field frequency and amplitude.

Abstract

The time-dependent exact-diagonalization method is used to study the light-induced phase transition of magnetic orders in the anisotropic triangular-lattice Hubbard model. Calculating the spin correlation function, we confirm that the phase transition from the 120$^{\circ}$ order to the N\'{e}el order can take place due to high-frequency periodic fields. We show that the effective Heisenberg-model Hamiltonian derived from the high-frequency expansion by the Floquet theory describes the present system very well and that the ratio of the exchange interactions expressed in terms of the frequency and amplitude of the external field determines the type of the magnetic orders. Our results demonstrate the controllability of the magnetic orders by tuning the external field.