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arXiv 2109.07973cond-mat.str-elcond-mat.mes-hall
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Shastry-Sutherland磁体中Skyrmion驱动的拓扑霍尔效应

Skyrmion-driven topological Hall effect in a Shastry-Sutherland magnet

N. Swain, M. Shahzad, G. V. Paradezhenko, A. A. Pervishko, D. Yudin, P. Sengupta

摘要:

Shastry-Sutherland模型及其推广已经被证明可以从几个准二维量子磁体的几何挫折中捕获涌现的复杂磁性。使用$sd$交换模型,我们在这里表明,金属Shastry-Sutherland磁体可以表现出拓扑霍尔效应驱动的磁skyrmions在现实条件下。的磁性建模与竞争的对称海森堡和不对称Dzyaloshinskiii-Moriya交换相互作用,而巡游电子的自旋和本地化的时刻之间的耦合描述的磁输运行为。我们的研究结果,采用互补的蒙特卡罗模拟和一种新的机器学习分析,调查的磁相位,提供证据的扩展范围内的哈密顿参数的场驱动skyrmion晶体形成。通过建立一个有效的紧束缚模型,传导电子耦合到skyrmion晶格,我们清楚地证明了拓扑霍尔效应的外观。我们进一步阐述了有限温度对磁性和磁输运性质的影响。

英文摘要:

The Shastry-Sutherland model and its generalizations have been shown to capture emergent complex magnetic properties from geometric frustration in several quasi-two-dimensional quantum magnets. Using an $sd$ exchange model, we show here that metallic Shastry-Sutherland magnets can exhibit a topological Hall effect driven by magnetic skyrmions under realistic conditions. The magnetic properties are modeled with competing symmetric Heisenberg and asymmetric Dzyaloshinskii-Moriya exchange interactions, while a coupling between the spins of the itinerant electrons and the localized moments describes the magnetotransport behavior. Our results, employing complementary Monte Carlo simulations and a novel machine learning analysis to investigate the magnetic phases, provide evidence for field-driven skyrmion crystal formation for an extended range of Hamiltonian parameters. By constructing an effective tight-binding model of conduction electrons coupled to the skyrmion lattice, we clearly demonstrate the appearance of the topological Hall effect. We further elaborate on the effects of finite temperatures on both magnetic and magnetotransport properties.

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