Spontaneous atomic-scale magnetic skyrmion lattice in two dimensions
Spontaneous atomic-scale magnetic skyrmion lattice in two dimensions
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DOI：
10.1038/nphys2045
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发表时间：
2011-09-01
期刊：
影响因子：
19.6
通讯作者：
Bluegel, Stefan
中科院分区：
文献类型：
--
作者：
Heinze, Stefan;von Bergmann, Kirsten;Bluegel, Stefan
Skyrmions是一种具有粒子性质的受拓扑保护的场结构，在科学的各个领域发挥着重要的作用。最近，人们观察到块状磁体中的Skyrmions被外加磁场稳定。在这里，我们将原子长度尺度上的二维方天子晶格描述为Ir(111)表面上单原子层厚度的六方铁薄膜的磁性基态。利用自旋极化扫描隧道显微镜，我们可以在原子尺度上直接成像真实空间中的这种非共线自旋织构，并证明它与原子晶格是不相称的。借助于第一性原理计算，我们在离散晶格上建立了一个自旋模型，该模型将海森堡交换、四自旋和Dzyaloshinskii-Moriya相互作用的相互作用确定为这种磁态的微观起源。
Skyrmions are topologically protected field configurations with particle-like properties that play an important role in various fields of science. Recently, skyrmions have been observed to be stabilized by an external magnetic field in bulk magnets. Here, we describe a two-dimensional square lattice of skyrmions on the atomic length scale as the magnetic ground state of a hexagonal Fe film of one-atomic-layer thickness on the Ir(111) surface. Using spin-polarized scanning tunnelling microscopy we can directly image this non-collinear spin texture in real space on the atomic scale and demonstrate that it is incommensurate to the underlying atomic lattice. With the aid of first-principles calculations, we develop a spin model on a discrete lattice that identifies the interplay of Heisenberg exchange, the four-spin and the Dzyaloshinskii-Moriya interaction as the microscopic origin of this magnetic state.