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Autori principali: Chen, Xin, Zou, Jin, Song, Lipeng, Sun, Wei, Wu, Yiwen, Zhu, Luyao, Cheng, Xu, Wang, Duo, Sanyal, Biplab
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2510.17522
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author Chen, Xin
Zou, Jin
Song, Lipeng
Sun, Wei
Wu, Yiwen
Zhu, Luyao
Cheng, Xu
Wang, Duo
Sanyal, Biplab
author_facet Chen, Xin
Zou, Jin
Song, Lipeng
Sun, Wei
Wu, Yiwen
Zhu, Luyao
Cheng, Xu
Wang, Duo
Sanyal, Biplab
contents Whether a zero-moment antiferromagnet can host an intrinsic half-metallic ground state with a single-spin Fermi surface remains an open question in antiferromagnetic spintronics. Existing proposals in compensated magnets reach only transport analogues of this limit and do not realize a genuine AFM half-metallic ground state with a single-spin Fermi surface. Here we show that in two-dimensional altermagnets the Néel-vector orientation acts as an intrinsic knob for magnetic-space-group reduction that lifts the degeneracy between spin sectors. Using Janus monolayer Ta$_2$TeSeO as a realistic and clean platform and combining symmetry analysis with first-principles calculations, we demonstrate that rotating the Néel vector first breaks the relevant mirror symmetry, opening a gap in one spin sector of symmetry-related Weyl pairs, and then breaks the residual $C_{2z}$ symmetry, shifting the remaining Weyl cones in opposite energy directions so that a single spin sector retains a Fermi surface at the Fermi level. These two symmetry-lowering steps convert a compensated altermagnetic Weyl semimetal into an intrinsic AFM half-metal. The nearly degenerate in-plane magnetic anisotropy then enables reversible switching between the two spin channels using minute strain or weak anisotropic fields. Because this mechanism relies solely on Néel-vector-induced symmetry reduction, it provides a general low-power route to intrinsic half-metallicity in compensated altermagnetic Weyl semimetals.
format Preprint
id arxiv_https___arxiv_org_abs_2510_17522
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Néel-Vector-Orientation Induced Intrinsic Half-Metallicity in Two-Dimensional Altermagnets
Chen, Xin
Zou, Jin
Song, Lipeng
Sun, Wei
Wu, Yiwen
Zhu, Luyao
Cheng, Xu
Wang, Duo
Sanyal, Biplab
Mesoscale and Nanoscale Physics
Materials Science
Computational Physics
Whether a zero-moment antiferromagnet can host an intrinsic half-metallic ground state with a single-spin Fermi surface remains an open question in antiferromagnetic spintronics. Existing proposals in compensated magnets reach only transport analogues of this limit and do not realize a genuine AFM half-metallic ground state with a single-spin Fermi surface. Here we show that in two-dimensional altermagnets the Néel-vector orientation acts as an intrinsic knob for magnetic-space-group reduction that lifts the degeneracy between spin sectors. Using Janus monolayer Ta$_2$TeSeO as a realistic and clean platform and combining symmetry analysis with first-principles calculations, we demonstrate that rotating the Néel vector first breaks the relevant mirror symmetry, opening a gap in one spin sector of symmetry-related Weyl pairs, and then breaks the residual $C_{2z}$ symmetry, shifting the remaining Weyl cones in opposite energy directions so that a single spin sector retains a Fermi surface at the Fermi level. These two symmetry-lowering steps convert a compensated altermagnetic Weyl semimetal into an intrinsic AFM half-metal. The nearly degenerate in-plane magnetic anisotropy then enables reversible switching between the two spin channels using minute strain or weak anisotropic fields. Because this mechanism relies solely on Néel-vector-induced symmetry reduction, it provides a general low-power route to intrinsic half-metallicity in compensated altermagnetic Weyl semimetals.
title Néel-Vector-Orientation Induced Intrinsic Half-Metallicity in Two-Dimensional Altermagnets
topic Mesoscale and Nanoscale Physics
Materials Science
Computational Physics
url https://arxiv.org/abs/2510.17522