Topologically Protected Surface Altermagnetism on Antiferromagnets

Fuente: arXiv
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Autores principales: Leeb, Valentin, d'Ornellas, Peru, de Juan, Fernando, Grushin, Adolfo G.
Formato: Preprint
Publicado: 2026
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author Leeb, Valentin
d'Ornellas, Peru
de Juan, Fernando
Grushin, Adolfo G.
author_facet Leeb, Valentin
d'Ornellas, Peru
de Juan, Fernando
Grushin, Adolfo G.
contents Altermagnetism (AM) and its associated spin-transport phenomena are typically linked to spin-split electronic band structures in bulk materials. However, the crystal surface has a reduced symmetry with respect to the bulk, which can induce AM at the surface of conventional antiferromagnets (AFMs) $\unicode{x2013}$ a local effect which cannot be detected using bulk properties. In this work we define the symmetry conditions necessary for surface AM and show how it can be topologically protected, rendering it a robust effect. We provide a minimal model for one trivial and two topological examples of surface AM. We show that the spin spectral density, accessible by spin- and angle-resolved photoemission spectroscopy, can exhibit a $d$-wave-like altermagnetic character at the surface, even when the full band structure is completely spin degenerate. Our topological model describes the Dirac semimetal CuMnAs, which provides an existing realization of our theory. Our results identify crystal surfaces as a platform to realize robust, topology- and symmetry-driven unconventional magnetism beyond the bulk classification of magnetic materials.
format Preprint
id arxiv_https___arxiv_org_abs_2602_10108
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Topologically Protected Surface Altermagnetism on Antiferromagnets
Leeb, Valentin
d'Ornellas, Peru
de Juan, Fernando
Grushin, Adolfo G.
Strongly Correlated Electrons
Altermagnetism (AM) and its associated spin-transport phenomena are typically linked to spin-split electronic band structures in bulk materials. However, the crystal surface has a reduced symmetry with respect to the bulk, which can induce AM at the surface of conventional antiferromagnets (AFMs) $\unicode{x2013}$ a local effect which cannot be detected using bulk properties. In this work we define the symmetry conditions necessary for surface AM and show how it can be topologically protected, rendering it a robust effect. We provide a minimal model for one trivial and two topological examples of surface AM. We show that the spin spectral density, accessible by spin- and angle-resolved photoemission spectroscopy, can exhibit a $d$-wave-like altermagnetic character at the surface, even when the full band structure is completely spin degenerate. Our topological model describes the Dirac semimetal CuMnAs, which provides an existing realization of our theory. Our results identify crystal surfaces as a platform to realize robust, topology- and symmetry-driven unconventional magnetism beyond the bulk classification of magnetic materials.
title Topologically Protected Surface Altermagnetism on Antiferromagnets
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2602.10108