Switching the Magnetization in Quantum Antiferromagnets

Fuente: arXiv
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Main Authors: Bolsmann, Katrin, Khudoyberdiev, Asliddin, Uhrig, Götz S.
Format: Preprint
Published: 2023
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author Bolsmann, Katrin
Khudoyberdiev, Asliddin
Uhrig, Götz S.
author_facet Bolsmann, Katrin
Khudoyberdiev, Asliddin
Uhrig, Götz S.
contents The orientation of the order parameter of quantum magnets can be used to store information in a dense and efficient way. Switching this order parameter corresponds to writing data. To understand how this can be done, we study a precessional reorientation of the sublattice magnetization in an (an)isotropic quantum antiferromagnet induced by an applied magnetic field. We use a description including the leading quantum and thermal fluctuations, namely Schwinger boson mean-field theory, because this theory allows us to describe both ordered phases and the phases in between them, as is crucial for switching. An activation energy has to be overcome requiring a minimum applied field $h_\text{t}$ which is given essentially by the spin gap. It can be reduced significantly for temperatures approaching the Néel temperature facilitating switching. The time required for switching diverges when the field approaches $h_\text{t}$ which is the signature of an inertia in the magnetization dynamics. The temporal evolution of the magnetization and of the energy reveals signs of dephasing. The switched state has lost a part of its coherence because the magnetic modes do not evolve in phase.
format Preprint
id arxiv_https___arxiv_org_abs_2303_15398
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Switching the Magnetization in Quantum Antiferromagnets
Bolsmann, Katrin
Khudoyberdiev, Asliddin
Uhrig, Götz S.
Strongly Correlated Electrons
The orientation of the order parameter of quantum magnets can be used to store information in a dense and efficient way. Switching this order parameter corresponds to writing data. To understand how this can be done, we study a precessional reorientation of the sublattice magnetization in an (an)isotropic quantum antiferromagnet induced by an applied magnetic field. We use a description including the leading quantum and thermal fluctuations, namely Schwinger boson mean-field theory, because this theory allows us to describe both ordered phases and the phases in between them, as is crucial for switching. An activation energy has to be overcome requiring a minimum applied field $h_\text{t}$ which is given essentially by the spin gap. It can be reduced significantly for temperatures approaching the Néel temperature facilitating switching. The time required for switching diverges when the field approaches $h_\text{t}$ which is the signature of an inertia in the magnetization dynamics. The temporal evolution of the magnetization and of the energy reveals signs of dephasing. The switched state has lost a part of its coherence because the magnetic modes do not evolve in phase.
title Switching the Magnetization in Quantum Antiferromagnets
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2303.15398