Optical conductivity and orbital magnetization of Floquet vortex states

Fuente: arXiv
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Auteurs principaux: Ahmadabadi, Iman, Dehghani, Hossein, Hafezi, Mohammad
Format: Preprint
Publié: 2022
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author Ahmadabadi, Iman
Dehghani, Hossein
Hafezi, Mohammad
author_facet Ahmadabadi, Iman
Dehghani, Hossein
Hafezi, Mohammad
contents Motivated by recent experimental demonstrations of Floquet topological insulators, there have been several theoretical proposals for using structured light, either spatial or spectral, to create other properties such as flat band and vortex states. In particular, the generation of vortex states in a massive Dirac fermion insulator irradiated by light carrying nonzero orbital angular momentum (OAM) has been proposed [Kim et al. Phys. Rev. B 105, L081301(2022)]. Here, we evaluate the orbital magnetization and optical conductivity as physical observables for such a system. We show that the OAM of light induces nonzero orbital magnetization and current density. The orbital magnetization density increases linearly as a function of OAM degree. In certain regimes, we find that orbital magnetization density is independent of the system size, width, and Rabi frequency of light. It is shown that the orbital magnetization arising from our Floquet theory is large and can be probed by magnetometry measurements. Furthermore, we study the optical conductivity for various types of electron transitions between different states such as vortex, edge, and bulk that are present in the system. Based on conductance frequency peaks, a scheme for the detection of vortex states is proposed.
format Preprint
id arxiv_https___arxiv_org_abs_2204_09488
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Optical conductivity and orbital magnetization of Floquet vortex states
Ahmadabadi, Iman
Dehghani, Hossein
Hafezi, Mohammad
Mesoscale and Nanoscale Physics
Other Condensed Matter
Motivated by recent experimental demonstrations of Floquet topological insulators, there have been several theoretical proposals for using structured light, either spatial or spectral, to create other properties such as flat band and vortex states. In particular, the generation of vortex states in a massive Dirac fermion insulator irradiated by light carrying nonzero orbital angular momentum (OAM) has been proposed [Kim et al. Phys. Rev. B 105, L081301(2022)]. Here, we evaluate the orbital magnetization and optical conductivity as physical observables for such a system. We show that the OAM of light induces nonzero orbital magnetization and current density. The orbital magnetization density increases linearly as a function of OAM degree. In certain regimes, we find that orbital magnetization density is independent of the system size, width, and Rabi frequency of light. It is shown that the orbital magnetization arising from our Floquet theory is large and can be probed by magnetometry measurements. Furthermore, we study the optical conductivity for various types of electron transitions between different states such as vortex, edge, and bulk that are present in the system. Based on conductance frequency peaks, a scheme for the detection of vortex states is proposed.
title Optical conductivity and orbital magnetization of Floquet vortex states
topic Mesoscale and Nanoscale Physics
Other Condensed Matter
url https://arxiv.org/abs/2204.09488