Floquet-driven indirect exchange interaction mediated by topological insulator surface states

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Auteurs principaux: Ke, Modi, Asmar, Mahmoud M., Tse, Wang-Kong
Format: Preprint
Publié: 2023
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_version_ 1866913437481697280
author Ke, Modi
Asmar, Mahmoud M.
Tse, Wang-Kong
author_facet Ke, Modi
Asmar, Mahmoud M.
Tse, Wang-Kong
contents Light drives offer a potential tool for the dynamical control of magnetic interactions in matter. We theoretically investigate the indirect exchange coupling between two parallel chains of magnetic impurities on the surface of a topological insulator, driven by a time-periodic circularly polarized light field in the high-frequency, off-resonant regime. We derive a closed-form analytic expression for the spin susceptibility of the photon-dressed topological insulator surface states and obtain the irradiation dependence of the Ising, Heisenberg, and Dzyaloshinskii- Moriya exchange couplings between the impurity chains. Our results show a two-pronged modification of these exchange couplings by periodic drives. First, the Ruderman-Kittel-Kasuya-Yosida (RKKY) oscillation period of the exchange couplings can be extended by enhancing the driving strength. Second, increasing driving strength enhances the envelope of RKKY oscillations of the Ising type while suppressing those of the Heisenberg type and Dzyaloshinskii-Moriya type. Our work provides useful insights for realizing Floquet engineering of collinear and noncollinear indirect exchange interactions in topological insulating systems.
format Preprint
id arxiv_https___arxiv_org_abs_2305_11963
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Floquet-driven indirect exchange interaction mediated by topological insulator surface states
Ke, Modi
Asmar, Mahmoud M.
Tse, Wang-Kong
Mesoscale and Nanoscale Physics
Light drives offer a potential tool for the dynamical control of magnetic interactions in matter. We theoretically investigate the indirect exchange coupling between two parallel chains of magnetic impurities on the surface of a topological insulator, driven by a time-periodic circularly polarized light field in the high-frequency, off-resonant regime. We derive a closed-form analytic expression for the spin susceptibility of the photon-dressed topological insulator surface states and obtain the irradiation dependence of the Ising, Heisenberg, and Dzyaloshinskii- Moriya exchange couplings between the impurity chains. Our results show a two-pronged modification of these exchange couplings by periodic drives. First, the Ruderman-Kittel-Kasuya-Yosida (RKKY) oscillation period of the exchange couplings can be extended by enhancing the driving strength. Second, increasing driving strength enhances the envelope of RKKY oscillations of the Ising type while suppressing those of the Heisenberg type and Dzyaloshinskii-Moriya type. Our work provides useful insights for realizing Floquet engineering of collinear and noncollinear indirect exchange interactions in topological insulating systems.
title Floquet-driven indirect exchange interaction mediated by topological insulator surface states
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2305.11963