Exchange Surface Spin Waves in Type-A van der Waals Antiferromagnets

Fuente: arXiv
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Main Authors: Sun, Zhoujian, Li, Fuxiang, Bauer, Gerrit E. W., Tang, Ping
Format: Preprint
Published: 2025
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author Sun, Zhoujian
Li, Fuxiang
Bauer, Gerrit E. W.
Tang, Ping
author_facet Sun, Zhoujian
Li, Fuxiang
Bauer, Gerrit E. W.
Tang, Ping
contents Surface spin waves in the short-wavelength regime enable ultrafast, nanoscale magnon-based devices. Here we report the emergence of surface spin-wave excitations within the bulk magnon band gap of type-A van der Waals antiferromagnets composed of antiferromagnetically coupled ferromagnetic monolayers. In contrast to the magnetostatic Damon-Eshbach modes in magnetic slabs, these surface waves are pure exchange modes owing to the reduced interlayer exchange coupling at surface layers, and thus persist in ultrathin multilayer stacks and at large wave numbers. We show that they can be efficiently excited by electromagnetic waves, with absorption power comparable to or even exceeding that of bulk modes. Moreover, their magnetic stray fields exhibit pronounced even-odd oscillations with the number of monolayers that should be observable by NV-center magnetometry.
format Preprint
id arxiv_https___arxiv_org_abs_2504_21465
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exchange Surface Spin Waves in Type-A van der Waals Antiferromagnets
Sun, Zhoujian
Li, Fuxiang
Bauer, Gerrit E. W.
Tang, Ping
Mesoscale and Nanoscale Physics
Surface spin waves in the short-wavelength regime enable ultrafast, nanoscale magnon-based devices. Here we report the emergence of surface spin-wave excitations within the bulk magnon band gap of type-A van der Waals antiferromagnets composed of antiferromagnetically coupled ferromagnetic monolayers. In contrast to the magnetostatic Damon-Eshbach modes in magnetic slabs, these surface waves are pure exchange modes owing to the reduced interlayer exchange coupling at surface layers, and thus persist in ultrathin multilayer stacks and at large wave numbers. We show that they can be efficiently excited by electromagnetic waves, with absorption power comparable to or even exceeding that of bulk modes. Moreover, their magnetic stray fields exhibit pronounced even-odd oscillations with the number of monolayers that should be observable by NV-center magnetometry.
title Exchange Surface Spin Waves in Type-A van der Waals Antiferromagnets
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2504.21465