Topological transition from nodal to nodeless Zeeman splitting in altermagnets

Fuente: arXiv
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Autori principali: Fernandes, Rafael M., de Carvalho, Vanuildo S., Birol, Turan, Pereira, Rodrigo G.
Natura: Preprint
Pubblicazione: 2023
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author Fernandes, Rafael M.
de Carvalho, Vanuildo S.
Birol, Turan
Pereira, Rodrigo G.
author_facet Fernandes, Rafael M.
de Carvalho, Vanuildo S.
Birol, Turan
Pereira, Rodrigo G.
contents In an altermagnet, the symmetry that relates configurations with flipped magnetic moments is a rotation. This makes it qualitatively different from a ferromagnet, where no such symmetry exists, or a collinear antiferromagnet, where this symmetry is a lattice translation. In this paper, we investigate the impact of the crystalline environment, enabled by the spin-orbit coupling, on the magnetic and electronic properties of an altermagnet. We find that, because each component of the magnetization acquires its own angular dependence, the Zeeman splitting of the bands has symmetry-protected nodal lines residing on mirror planes of the crystal. Upon crossing the Fermi surface, these nodal lines give rise to pinch points that behave as single or double type-II Weyl nodes. We show that an external magnetic field perpendicular to these mirror planes can only move the nodal lines, such that a critical field value is necessary to collapse the nodes and make the Weyl pinch points annihilate. This unveils the topological nature of the transition from a nodal to a nodeless Zeeman splitting of the bands. We also classify the altermagnetic states of common crystallographic point groups in the presence of spin-orbit coupling, revealing that a broad family of magnetic orthorhombic perovskites can realize altermagnetism.
format Preprint
id arxiv_https___arxiv_org_abs_2307_12380
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Topological transition from nodal to nodeless Zeeman splitting in altermagnets
Fernandes, Rafael M.
de Carvalho, Vanuildo S.
Birol, Turan
Pereira, Rodrigo G.
Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
In an altermagnet, the symmetry that relates configurations with flipped magnetic moments is a rotation. This makes it qualitatively different from a ferromagnet, where no such symmetry exists, or a collinear antiferromagnet, where this symmetry is a lattice translation. In this paper, we investigate the impact of the crystalline environment, enabled by the spin-orbit coupling, on the magnetic and electronic properties of an altermagnet. We find that, because each component of the magnetization acquires its own angular dependence, the Zeeman splitting of the bands has symmetry-protected nodal lines residing on mirror planes of the crystal. Upon crossing the Fermi surface, these nodal lines give rise to pinch points that behave as single or double type-II Weyl nodes. We show that an external magnetic field perpendicular to these mirror planes can only move the nodal lines, such that a critical field value is necessary to collapse the nodes and make the Weyl pinch points annihilate. This unveils the topological nature of the transition from a nodal to a nodeless Zeeman splitting of the bands. We also classify the altermagnetic states of common crystallographic point groups in the presence of spin-orbit coupling, revealing that a broad family of magnetic orthorhombic perovskites can realize altermagnetism.
title Topological transition from nodal to nodeless Zeeman splitting in altermagnets
topic Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2307.12380