1] Max Planck Institute for Chemical Physics of Solids, D-01087 Dresden, Germany [2] National Institute of Chemical Physics and Biophysics, EE-12618 Tallinn, Estonia.
Leibniz Institute for Solid State and Materials Research, IFW D-01069 Dresden, Germany.
Nat Commun. 2014 Nov 4;5:5376. doi: 10.1038/ncomms6376.
The Skyrme-particle, the skyrmion, was introduced over half a century ago in the context of dense nuclear matter. But with skyrmions being mathematical objects--special types of topological solitons--they can emerge in much broader contexts. Recently skyrmions were observed in helimagnets, forming nanoscale spin-textures. Extending over length scales much larger than the interatomic spacing, they behave as large, classical objects, yet deep inside they are of quantum nature. Penetrating into their microscopic roots requires a multi-scale approach, spanning the full quantum to classical domain. Here, we achieve this for the first time in the skyrmionic Mott insulator Cu2OSeO3. We show that its magnetic building blocks are strongly fluctuating Cu4 tetrahedra, spawning a continuum theory that culminates in 51 nm large skyrmions, in striking agreement with experiment. One of the further predictions that ensues is the temperature-dependent decay of skyrmions into half-skyrmions.
Skyrme 粒子，即 skyrmion，半个多世纪前在致密核物质的背景下被引入。但是，由于 skyrmion 是数学对象——特殊类型的拓扑孤子——它们可以在更广泛的背景下出现。最近，在螺旋磁铁中观察到了 skyrmion，形成了纳米级的自旋织构。这些 skyrmion 延伸的长度尺度远远大于原子间的间距，它们表现为大的、经典的物体，但在其内部深处，它们具有量子特性。深入研究其微观根源需要一种多尺度的方法，跨越整个量子到经典领域。在这里，我们首次在 skyrmionic Mott 绝缘体 Cu2OSeO3 中实现了这一目标。我们表明，其磁性构建块是强烈波动的 Cu4 四面体，产生了一个连续统理论，最终得出了 51nm 大的 skyrmion，与实验结果非常吻合。随之而来的进一步预测之一是 skyrmion 会在温度依赖的情况下衰减为半 skyrmion。
