Universal spin wavepacket transport in van der Waals antiferromagnets

Fuente: arXiv
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Main Authors: Sun, Yue, Meng, Fanhao, Lee, Changmin, Soll, Aljoscha, Zhang, Hongrui, Ramesh, Ramamoorthy, Yao, Jie, Sofer, Zdenĕk, Orenstein, Joseph
Format: Preprint
Published: 2023
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author Sun, Yue
Meng, Fanhao
Lee, Changmin
Soll, Aljoscha
Zhang, Hongrui
Ramesh, Ramamoorthy
Yao, Jie
Sofer, Zdenĕk
Orenstein, Joseph
author_facet Sun, Yue
Meng, Fanhao
Lee, Changmin
Soll, Aljoscha
Zhang, Hongrui
Ramesh, Ramamoorthy
Yao, Jie
Sofer, Zdenĕk
Orenstein, Joseph
contents Antiferromagnets (AFMs) are promising platforms for the transmission of quantum information via magnons (the quanta of spin waves), offering advantages over ferromagnets with regard to dissipation, speed of response, and immunity to external fields. Recently, it was shown that in the insulating van der Waals (vdW) semiconductor, CrSBr, strong spin-exciton coupling enables readout of magnon density and propagation using photons of visible light. This exciting observation came with a puzzle: photogenerated magnons were observed to propagate 10$^3$ times faster than the velocity inferred from neutron scattering, leading to a conjecture that spin wavepackets are carried along by coupling to much faster elastic modes. Here we show, through a combination of theory and experiment, that the propagation mechanism is, instead, coupling within the magnetic degrees of freedom through long range dipole-dipole coupling. This mechanism is an inevitable consequence of Maxwell's equations, and as such, will dominate the propagation of spin at long wavelengths in the entire class of vdW magnets currently under intense investigation. Moreover, identifying the mechanism of spin propagation provides a set of optimization rules, as well as caveats, that are essential for any future applications of these promising systems.
format Preprint
id arxiv_https___arxiv_org_abs_2309_03278
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Universal spin wavepacket transport in van der Waals antiferromagnets
Sun, Yue
Meng, Fanhao
Lee, Changmin
Soll, Aljoscha
Zhang, Hongrui
Ramesh, Ramamoorthy
Yao, Jie
Sofer, Zdenĕk
Orenstein, Joseph
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Antiferromagnets (AFMs) are promising platforms for the transmission of quantum information via magnons (the quanta of spin waves), offering advantages over ferromagnets with regard to dissipation, speed of response, and immunity to external fields. Recently, it was shown that in the insulating van der Waals (vdW) semiconductor, CrSBr, strong spin-exciton coupling enables readout of magnon density and propagation using photons of visible light. This exciting observation came with a puzzle: photogenerated magnons were observed to propagate 10$^3$ times faster than the velocity inferred from neutron scattering, leading to a conjecture that spin wavepackets are carried along by coupling to much faster elastic modes. Here we show, through a combination of theory and experiment, that the propagation mechanism is, instead, coupling within the magnetic degrees of freedom through long range dipole-dipole coupling. This mechanism is an inevitable consequence of Maxwell's equations, and as such, will dominate the propagation of spin at long wavelengths in the entire class of vdW magnets currently under intense investigation. Moreover, identifying the mechanism of spin propagation provides a set of optimization rules, as well as caveats, that are essential for any future applications of these promising systems.
title Universal spin wavepacket transport in van der Waals antiferromagnets
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2309.03278