Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan.
Department of Physics, The University of Tokyo, Tokyo, 113-0033, Japan.
Nat Commun. 2019 Mar 15;10(1):1229. doi: 10.1038/s41467-019-09063-7.
Geometrical frustration and a high magnetic field are two key factors for realizing unconventional quantum states in magnetic materials. Specifically, conventional magnetic order can potentially be destroyed by competing interactions and may be replaced by an exotic state that is characterized in terms of quasiparticles called magnons, the density and chemical potential of which are controlled by the magnetic field. Here we show that a synthetic copper mineral, Cd-kapellasite, which comprises a kagomé lattice consisting of corner-sharing triangles of spin-1/2 Cu ions, exhibits an unprecedented series of fractional magnetization plateaus in ultrahigh magnetic fields of up to 160 T. We propose that these quantum states can be interpreted as crystallizations of emergent magnons localized on the hexagon of the kagomé lattice.
几何阻挫和强磁场是在磁性材料中实现非常规量子态的两个关键因素。具体来说，竞争相互作用有可能破坏常规磁序，并可能被一种奇特的量子态所取代，这种量子态的特征是准粒子，称为磁振子，其密度和化学势由磁场控制。在这里，我们展示了一种合成的铜矿物 Cd-kapellasite，它由由自旋为 1/2 的 Cu 离子共享顶角的三角形组成的 kagomé 晶格组成，在高达 160 T 的超高磁场中表现出一系列前所未有的分数磁化平台。我们提出，这些量子态可以被解释为在 kagomé 晶格的六边形上局域化的涌现磁振子的结晶。
