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Main Authors: Rasmussen, Christian L. H., Gondolf, Jannik, Barkman, Mats, Roig, Mercè, Agterberg, Daniel F., Kreisel, Andreas, Andersen, Brian M.
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.03247
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author Rasmussen, Christian L. H.
Gondolf, Jannik
Barkman, Mats
Roig, Mercè
Agterberg, Daniel F.
Kreisel, Andreas
Andersen, Brian M.
author_facet Rasmussen, Christian L. H.
Gondolf, Jannik
Barkman, Mats
Roig, Mercè
Agterberg, Daniel F.
Kreisel, Andreas
Andersen, Brian M.
contents Altermagnetic metals break time-reversal symmetry and feature spin-split Fermi surfaces generated by compensated Néel-ordered collinear magnetic moments. Being metallic, such altermagnets may undergo a further instability at low temperatures to a superconducting state, and it is an interesting open question what the salient features are of such altermagnetic superconductors. We address this question on the basis of realistic microscopic models that capture the altermagnetic sublattice degrees of freedom. We find that the sublattice structure can strongly affect the superconducting gap structure in altermagnetic superconductors. In particular, it imposes nodes in the gap on the Brillouin zone edges for superconductors stabilized by momentum-independent bare attraction channels. We contrast this to the case of superconductivity generated by extended range interactions where pairing is allowed on the Brillouin zone edges and both spin-singlet and equal-spin-pairing triplet states can be stabilized. Equal-spin-pairing triplet superconductivity is generically favored in the limit of large altermagnetic spin splitting of the bands compared to the superconducting gap scale, and features characteristic nonunitary properties arising from the altermagnetic order.
format Preprint
id arxiv_https___arxiv_org_abs_2509_03247
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Inherent momentum-dependent gap structure of altermagnetic superconductors
Rasmussen, Christian L. H.
Gondolf, Jannik
Barkman, Mats
Roig, Mercè
Agterberg, Daniel F.
Kreisel, Andreas
Andersen, Brian M.
Superconductivity
Altermagnetic metals break time-reversal symmetry and feature spin-split Fermi surfaces generated by compensated Néel-ordered collinear magnetic moments. Being metallic, such altermagnets may undergo a further instability at low temperatures to a superconducting state, and it is an interesting open question what the salient features are of such altermagnetic superconductors. We address this question on the basis of realistic microscopic models that capture the altermagnetic sublattice degrees of freedom. We find that the sublattice structure can strongly affect the superconducting gap structure in altermagnetic superconductors. In particular, it imposes nodes in the gap on the Brillouin zone edges for superconductors stabilized by momentum-independent bare attraction channels. We contrast this to the case of superconductivity generated by extended range interactions where pairing is allowed on the Brillouin zone edges and both spin-singlet and equal-spin-pairing triplet states can be stabilized. Equal-spin-pairing triplet superconductivity is generically favored in the limit of large altermagnetic spin splitting of the bands compared to the superconducting gap scale, and features characteristic nonunitary properties arising from the altermagnetic order.
title Inherent momentum-dependent gap structure of altermagnetic superconductors
topic Superconductivity
url https://arxiv.org/abs/2509.03247