Year: 2018
Type: article
Abstract: We study the photoinduced magnetic transition in an itinerant magnet described by the double-exchange model, in which conduction electrons couple with localized spins through the ferromagnetic (FM) Hund coupling. It is shown that intense light applied to the FM ground state induces an antiferromagnetic (AFM) order, in contrast to the AFM-to-FM transition due to the photocarrier injection. In particular, we focus on the mechanism for instability of the FM structure by the light irradiation. The magnon spectrum in the Floquet state is formulated on the basis of the perturbative expansion of the Floquet Green's function. The magnon dispersion shows softening at momentum $(\ensuremath{\pi},\ensuremath{\pi})$ in the square lattice with increasing the light amplitude, implying photoinduced AFM instability. This result is mainly attributed to a nonequilibrium electron distribution, which promotes low-energy Stoner excitations. The transient optical conductivity spectra characterized by interband excitations and Floquet sidepeaks are available to identify the photoinduced AFM state.
Authors: Atsushi Ono, Sumio Ishihara
Institution: Tohoku University
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: Development of novel photo-induced phase conversion materials based on quantum dynamics control of Charge-Structure-Spin-Photon coupled systems, Electronic State of Excitonic Insulator from viewpoint of Orbital Physics, 強相関遍歴磁性体における光による高速磁性制御の理論, Dynamical localization and photoinduced construction of electronic orders in strongly correlated system
OpenAlex ID: W2890817950