Total angular momentum dichroism of the terahertz vortex beams at the antiferromagnetic resonances

Terahertz vortex beams with different superposition of the orbital angular momentum \(l={\pm}1\), \({\pm}2\), \({\pm}3\), and \({\pm}4\) and spin angular momentum \({\sigma}={\pm}1\) were used to study antiferromagnetic (AFM) resonances in TbFe\(_3\)(BO\(_3\))\(_4\) and Ni\(_3\)TeO\(_6\) single crys...

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Bibliographic Details
Published in:arXiv.org 2021-03
Main Authors: Sirenko, A A, Marsik, P, Bugnon, L, Soulier, M, Bernhard, C, Stanislavchuk, T N, S -W Cheong
Format: Article
Language:English
Subjects:
Angular momentum
Antiferromagnetism
Circular polarization
Dichroism
Electron beams
Orbital resonances (celestial mechanics)
Single crystals
Vortices
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Summary:Terahertz vortex beams with different superposition of the orbital angular momentum \(l={\pm}1\), \({\pm}2\), \({\pm}3\), and \({\pm}4\) and spin angular momentum \({\sigma}={\pm}1\) were used to study antiferromagnetic (AFM) resonances in TbFe\(_3\)(BO\(_3\))\(_4\) and Ni\(_3\)TeO\(_6\) single crystals. In both materials we observed a strong vortex beam dichroism for the AFM resonances that are split in external magnetic field. The magnitude of the vortex dichroism is comparable to that for conventional circular dichroism due to \({\sigma}\). The selection rules at the AFM resonances are governed by the total angular momentum of the vortex beam: \(j={\sigma}+l\). In particular, for \(l={\pm}2\), \({\pm}3\), and \({\pm}4\) the sign of \(l\) is shown to dominate over that for conventional circular polarization \({\sigma}\).
ISSN:2331-8422
DOI:10.48550/arxiv.2008.08670