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arXiv 2501.13486cond-mat.mes-hall
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强外部磁场下磁单弦的径向稳定化

Radial Stabilization of Magnetic Skyrmions Under Strong External Magnetic Field

National Research and Innovation Agency (BRIN)(国家研究与创新署);Institut Teknologi Bandung(万隆理工学院)

Emir Syahreza Fadhilla, M Shoufie Ukhtary, Ardian Nata Atmaja, Bobby Eka Gunara

AI总结:

本研究提出了一种在强外部磁场下保持稳定的磁单弦模型,通过q²项保持反演对称性,揭示了单弦在极端磁场条件下的拓扑稳定性。

摘要:

磁单弦数密度,q≡n·(∂_x n×∂_y n)/(4π),是表征磁单弦拓扑性质的关键量之一。在本工作中,我们提出了一种二维磁性系统模型,其哈密顿量包含一个与q²成正比的相互作用项,该项保持反演对称性。所提出的q²项也被称为Skyrme项,是三维霍夫离子模型中熟知的四次项的二维版本。与通常的交换相互作用不同,q²项在强外部磁场极限下仍保持存在。利用Landau-Lifshitz-Gilbert方程进行微磁学计算,我们表明该模型的最低能量配置表现出单弦特性。此外,该配置在小的线性径向对称扰动下仍保持稳定,并且我们证明了系统的总能量被下界所限制,确保其始终高于真空能量。这表明了一个拓扑保护的配置。我们的模型提供了一个框架,用于描述没有破坏反演对称性的材料中的单弦,特别是在受到强外部磁场作用的系统中,其中传统交换相互作用显著弱于Zeeman效应。

英文摘要:

The skyrmion number density, $q\equiv\vec{n}\cdot\left(\partial_x\vec{n}\times\partial_y\vec{n}\right)/(4π)$, is one of the key quantities that characterizes the topological properties of a magnetic skyrmion. In this work, we propose a model for a two-dimensional magnetic system with Hamiltonian that contains an interaction term proportional to $q^2$ which preserves inversion symmetry. The proposed $q^2$ term is also known as the Skyrme term and is a two-dimensional version of the well-known quartic term in models of three-dimensional Hopfions. In contrast with the usual exchange interaction, the $q^2$ term persists at the strong external magnetic field limit. Using the Landau-Lifshitz-Gilbert equation for micromagnetic calculations, we show that the minimum energy configuration of this model exhibits skyrmion properties. Furthermore, this configuration remains stable under small linear radially symmetric perturbations, and we demonstrate that the total energy of the system is bounded from below, ensuring that it remains above the vacuum energy. This implies a topologically protected configuration. Our model provides a framework for describing skyrmions in materials without broken inversion symmetry, particularly in systems subjected to strong external magnetic fields, where conventional exchange interactions are significantly weaker than the Zeeman effect.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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