The fate of $p$-wave spin polarization in helimagnets with Rashba spin-orbit coupling

Fuente: arXiv
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Main Authors: Hodt, Erik Wegner, Bentmann, Hendrik, Linder, Jacob
Format: Preprint
Published: 2024
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author Hodt, Erik Wegner
Bentmann, Hendrik
Linder, Jacob
author_facet Hodt, Erik Wegner
Bentmann, Hendrik
Linder, Jacob
contents It has recently been realized that magnetic systems with coplanar magnetic order that are invariant under the combined operation of time-reversal and translation with half a unit cell feature energy bands with a symmetry-protected p-wave spin polarization. Such $p$-wave magnets are a sought-after spin analogy of unconventional triplet superconducting pairing and show promise for use in spintronics. Metallic helimagnets provide a realization of $p$-wave magnetism, but such order often occurs in systems lacking inversion symmetry so that Rashba spin-orbit interactions can be prominent. An important question is therefore how the magnitude and the existence of $p$-wave spin polarization is affected by Rashba spin-orbit interaction. Here, we prove that while the $p$-wave symmetry of the spin-polarized bands is strictly speaking removed by such spin-orbit interactions in helimagnets unless the period of the helix is fine-tuned, the actual quantitative deviation from $p$-wave symmetry is extremely weak unless the period of the helix is only a few lattice sites. Thereafter, we show that the $p$-wave magnetism becomes completely robust in pairs of antiferromagnetically coupled helices. More precisely, the $p$-wave spin-polarization of the bands then appears regardless of the periodicity and regardless of the strength of the spin-orbit interactions. This shows that antiferromagnetically coupled helimagnetic chains produce robust $p$-wave spin polarization free of fine-tuning requirements, making them attractive for potential spintronic applications.
format Preprint
id arxiv_https___arxiv_org_abs_2412_12246
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The fate of $p$-wave spin polarization in helimagnets with Rashba spin-orbit coupling
Hodt, Erik Wegner
Bentmann, Hendrik
Linder, Jacob
Mesoscale and Nanoscale Physics
It has recently been realized that magnetic systems with coplanar magnetic order that are invariant under the combined operation of time-reversal and translation with half a unit cell feature energy bands with a symmetry-protected p-wave spin polarization. Such $p$-wave magnets are a sought-after spin analogy of unconventional triplet superconducting pairing and show promise for use in spintronics. Metallic helimagnets provide a realization of $p$-wave magnetism, but such order often occurs in systems lacking inversion symmetry so that Rashba spin-orbit interactions can be prominent. An important question is therefore how the magnitude and the existence of $p$-wave spin polarization is affected by Rashba spin-orbit interaction. Here, we prove that while the $p$-wave symmetry of the spin-polarized bands is strictly speaking removed by such spin-orbit interactions in helimagnets unless the period of the helix is fine-tuned, the actual quantitative deviation from $p$-wave symmetry is extremely weak unless the period of the helix is only a few lattice sites. Thereafter, we show that the $p$-wave magnetism becomes completely robust in pairs of antiferromagnetically coupled helices. More precisely, the $p$-wave spin-polarization of the bands then appears regardless of the periodicity and regardless of the strength of the spin-orbit interactions. This shows that antiferromagnetically coupled helimagnetic chains produce robust $p$-wave spin polarization free of fine-tuning requirements, making them attractive for potential spintronic applications.
title The fate of $p$-wave spin polarization in helimagnets with Rashba spin-orbit coupling
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2412.12246