Topological Magnon Bands in a Kagome Lattice Ferromagnet
Topological Magnon Bands in a Kagome Lattice Ferromagnet
复制标题
DOI：
10.1103/physrevlett.115.147201
复制
发表时间：
2015-09-28
影响因子：
8.6
通讯作者：
Lee, Y. S.
中科院分区：
文献类型：
--
作者：
Chisnell, R.;Helton, J. S.;Lee, Y. S.
人们对寻找具有拓扑性质的准粒子材料有着极大的兴趣。这种材料可能具有存在于其边界上的新颖的激发，其被保护免于无序。我们报告的实验证据表明，磁振子在绝缘戈薇铁磁体可以有一个拓扑能带结构。我们的中子散射测量进一步揭示了其中一个带是平坦的，这是由于可果美晶格的独特几何结构。自旋波计算表明，测量的能带结构如下从一个简单的海森堡哈密顿与Dzyaloshinkii-Moriya相互作用。这是第一次实现一个有效的二维拓扑磁振子绝缘体-一类新的磁性材料，应显示磁振子霍尔效应和保护手性边缘模式。
There is great interest in finding materials possessing quasiparticles with topological properties. Such materials may have novel excitations that exist on their boundaries which are protected against disorder. We report experimental evidence that magnons in an insulating kagome ferromagnet can have a topological band structure. Our neutron scattering measurements further reveal that one of the bands is flat due to the unique geometry of the kagome lattice. Spin wave calculations show that the measured band structure follows from a simple Heisenberg Hamiltonian with a Dzyaloshinkii-Moriya interaction. This serves as the first realization of an effectively two-dimensional topological magnon insulator-a new class of magnetic material that should display both a magnon Hall effect and protected chiral edge modes.