论文标题
中心对称巡回磁铁中的Sky Skyrmion晶体
Square skyrmion crystal in centrosymmetric itinerant magnets
论文作者
论文摘要
从理论上讲，我们从Centrosymmortric巡回磁铁中研究了方形Skyrmion Crystal的起源，这是由于最近在GDRU $ _2 $ _2 $ si $ _2 $ [N.中的实验发现的动机。 D. Khanh $ \ Mathit {et} $ $ \ Mathit {al。} $，nat。纳米技术。 $ \ mathbf {15} $，444（2020）]。通过模拟在正方形晶格上衍生自Kondo晶格模型的有效自旋模型的退火，我们发现正方形的Skyrmion晶体由两个旋转螺旋的叠加组成，在磁场中通过磁场稳定在磁场中，通过阳性生物质量，键合，键相依赖的型偏置型偏置型和易于轴轴测轴心相互作用。这与仅由三个稳定的三角形天际晶体形成鲜明对比，这表明方形的晶体是带有磁各向异性的巡回磁铁的特征。我们还表明，根据模型参数以及施加的磁场，各种非共线和非Coplanar自旋纹理出现。本系统的研究不仅对识别GDRU $ _2 $ si $ _2 $中的关键成分有用，而且对于探索Centrosymmmetric Atinerant Magnets中的进一步的Skyrmion托管材料。
We theoretically investigate the origin of the square-type skyrmion crystal in centrosymmetric itinerant magnets, motivated from the recent experimental finding in GdRu$_2$Si$_2$ [N. D. Khanh $\mathit{et}$ $\mathit{al.}$, Nat. Nanotech. $\mathbf{15}$, 444 (2020)]. By simulated annealing for an effective spin model derived from the Kondo lattice model on a square lattice, we find that a square skyrmion crystal composed of a superposition of two spin helices is stabilized in a magnetic field by synergy between the positive biquadratic, bond-dependent anisotropic, and easy-axis anisotropic interactions. This is in stark contrast to triangular skyrmion crystals which are stabilized by only one of the three, suggesting that the square skyrmion crystal is characteristic of itinerant magnets with magnetic anisotropy. We also show that a variety of noncollinear and noncoplanar spin textures appear depending on the model parameters as well as the applied magnetic field. The present systematic study will be useful not only for identifying the key ingredients in GdRu$_2$Si$_2$ but also for exploring further skyrmion-hosting materials in centrosymmetric itinerant magnets.
