Theory of bound magnetic polarons in cubic and uniaxial antiferromagnets

Fuente: arXiv
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Main Authors: Bugajewski, Dawid, Autieri, Carmine, Dietl, Tomasz
Format: Preprint
Published: 2025
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author Bugajewski, Dawid
Autieri, Carmine
Dietl, Tomasz
author_facet Bugajewski, Dawid
Autieri, Carmine
Dietl, Tomasz
contents Motivated by a recent debate about the origin of remanent magnetization and the corresponding anomalous Hall effect in antiferromagnets and altermagnets, a theory of bound magnetic polarons (BMPs) in anisotropic antiferromagnetic semiconductors is developed. The theory describes quantitatively the experimentally observed magnitude of excess magnetization and its dependence on the magnetic field in cubic antiferromagnetic EuTe. In contrast to the cubic case, our theory predicts the presence of magnetization hysteresis below Néel temperature in antiferromagnets with uniaxial anisotropy. We show, employing material parameters implied by experimental and ab initio results, that the magnitudes of remanent magnetization and the coercive field are in accord with recent experimental observations for altermagnetic hexagonal MnTe. While the altermagnets have an intrinsic contribution to the remanent magnetization and the anomalous Hall effect, our theory explains the origin of an extrinsic contribution. Our findings address, therefore, a question about the relative contribution to the remanent magnetization of bound magnetic polarons and weak ferromagnetism driven by the antisymmetric exchange interaction, the latter weakened by the formation of antiferromagnetic domains. Furthermore, we provide the theory of BMP spontaneous spin splitting, which can be probed optically.
format Preprint
id arxiv_https___arxiv_org_abs_2506_10208
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Theory of bound magnetic polarons in cubic and uniaxial antiferromagnets
Bugajewski, Dawid
Autieri, Carmine
Dietl, Tomasz
Mesoscale and Nanoscale Physics
Materials Science
Motivated by a recent debate about the origin of remanent magnetization and the corresponding anomalous Hall effect in antiferromagnets and altermagnets, a theory of bound magnetic polarons (BMPs) in anisotropic antiferromagnetic semiconductors is developed. The theory describes quantitatively the experimentally observed magnitude of excess magnetization and its dependence on the magnetic field in cubic antiferromagnetic EuTe. In contrast to the cubic case, our theory predicts the presence of magnetization hysteresis below Néel temperature in antiferromagnets with uniaxial anisotropy. We show, employing material parameters implied by experimental and ab initio results, that the magnitudes of remanent magnetization and the coercive field are in accord with recent experimental observations for altermagnetic hexagonal MnTe. While the altermagnets have an intrinsic contribution to the remanent magnetization and the anomalous Hall effect, our theory explains the origin of an extrinsic contribution. Our findings address, therefore, a question about the relative contribution to the remanent magnetization of bound magnetic polarons and weak ferromagnetism driven by the antisymmetric exchange interaction, the latter weakened by the formation of antiferromagnetic domains. Furthermore, we provide the theory of BMP spontaneous spin splitting, which can be probed optically.
title Theory of bound magnetic polarons in cubic and uniaxial antiferromagnets
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2506.10208