Altermagnetism Without Crystal Symmetry

Fuente: arXiv
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Hauptverfasser: d'Ornellas, Peru, Leeb, Valentin, Grushin, Adolfo G., Knolle, Johannes
Format: Preprint
Veröffentlicht: 2025
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author d'Ornellas, Peru
Leeb, Valentin
Grushin, Adolfo G.
Knolle, Johannes
author_facet d'Ornellas, Peru
Leeb, Valentin
Grushin, Adolfo G.
Knolle, Johannes
contents Altermagnetism is a collinear magnetic order in which opposite spin species are exchanged under a real-space rotation. Hence, the search for physical realizations has focussed on crystalline solids with specific rotational symmetry. Here, we show that altermagnetism can also emerge in non-crystalline systems, such as amorphous solids, despite the lack of global rotational symmetries. We construct a Hamiltonian with two directional orbitals per site on an amorphous lattice with interactions that are invariant under spin rotation. Altermagnetism then arises due to spontaneous symmetry breaking in the spin and orbital degrees of freedom around each atom, displaying a common point group symmetry. This form of altermagnetism exhibits anisotropic spin transport and spin spectral functions, both experimentally measurable. Our mechanism generalizes to any lattice and any altermagnetic order, opening the search for altermagnetic phenomena to non-crystalline systems.
format Preprint
id arxiv_https___arxiv_org_abs_2504_08597
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Altermagnetism Without Crystal Symmetry
d'Ornellas, Peru
Leeb, Valentin
Grushin, Adolfo G.
Knolle, Johannes
Strongly Correlated Electrons
Disordered Systems and Neural Networks
Altermagnetism is a collinear magnetic order in which opposite spin species are exchanged under a real-space rotation. Hence, the search for physical realizations has focussed on crystalline solids with specific rotational symmetry. Here, we show that altermagnetism can also emerge in non-crystalline systems, such as amorphous solids, despite the lack of global rotational symmetries. We construct a Hamiltonian with two directional orbitals per site on an amorphous lattice with interactions that are invariant under spin rotation. Altermagnetism then arises due to spontaneous symmetry breaking in the spin and orbital degrees of freedom around each atom, displaying a common point group symmetry. This form of altermagnetism exhibits anisotropic spin transport and spin spectral functions, both experimentally measurable. Our mechanism generalizes to any lattice and any altermagnetic order, opening the search for altermagnetic phenomena to non-crystalline systems.
title Altermagnetism Without Crystal Symmetry
topic Strongly Correlated Electrons
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2504.08597