Orbital-spin Locking and its Optical Signatures in Altermagnets

Fuente: arXiv
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Auteurs principaux: Vila, Marc, Sunko, Veronika, Moore, Joel E.
Format: Preprint
Publié: 2024
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author Vila, Marc
Sunko, Veronika
Moore, Joel E.
author_facet Vila, Marc
Sunko, Veronika
Moore, Joel E.
contents Altermagnets, magnetic materials with zero magnetization and spin-split band structure, have gained tremendous attention recently for their rich physics and potential applications. Here, we report on a microscopic tight-binding model that unveils a unique coupling between orbitals and spins in $d$-wave altermagnets which gives rise to momentum-dependent and spin-selective optical absorption. This coupling promotes the controlled optical excitation of up or down spins depending on the polarization direction of linearly polarized light. Such an effect originates from the coupling of orbitals to the sublattice degree of freedom through the crystal field, which is then coupled to spins through the antiferromagnetic interaction. Our crystal field analysis, which is general to any type of altermagnet, helps understand the onset of altermagnetism from a microscopic point of view, and we use our results to propose clear magneto-optical signatures of our predictions. Our findings shine light on the interplay between orbitals and spins in altermagnets, thus paving the way towards novel orbitronic and opto-spintronic devices.
format Preprint
id arxiv_https___arxiv_org_abs_2410_23513
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Orbital-spin Locking and its Optical Signatures in Altermagnets
Vila, Marc
Sunko, Veronika
Moore, Joel E.
Materials Science
Mesoscale and Nanoscale Physics
Altermagnets, magnetic materials with zero magnetization and spin-split band structure, have gained tremendous attention recently for their rich physics and potential applications. Here, we report on a microscopic tight-binding model that unveils a unique coupling between orbitals and spins in $d$-wave altermagnets which gives rise to momentum-dependent and spin-selective optical absorption. This coupling promotes the controlled optical excitation of up or down spins depending on the polarization direction of linearly polarized light. Such an effect originates from the coupling of orbitals to the sublattice degree of freedom through the crystal field, which is then coupled to spins through the antiferromagnetic interaction. Our crystal field analysis, which is general to any type of altermagnet, helps understand the onset of altermagnetism from a microscopic point of view, and we use our results to propose clear magneto-optical signatures of our predictions. Our findings shine light on the interplay between orbitals and spins in altermagnets, thus paving the way towards novel orbitronic and opto-spintronic devices.
title Orbital-spin Locking and its Optical Signatures in Altermagnets
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2410.23513