论文标题
沮丧的量子抗Fiferromagnet CS $ _2 $ COBR $ _4 $
Magnetization plateaux cascade in the frustrated quantum antiferromagnet Cs$_2$CoBr$_4$
论文作者
论文摘要
我们在2D量子抗Fromagnet CS $ _2 $ COBR $ _4 $中发现了两种挫败机制的不寻常竞争。关键参与者是单个磁性Co $^{2+} $离子的单离子平面各向异性方向的交替，及其在扭曲的三角形晶格结构中的排列。特别是，唯一的定向的Ising型各向异性是从易于平面的竞争中出现的，对于沿该轴施加的磁场，在低温下发现了五个有序相的级联。这些阶段中的两个具有磁化高原。低场应该是通过各向异性稳定的共线基态的结果，而另一个高原具有“上向上”状态的特征，用于具有三角形交换模式的晶格。磁化高原的这种共存是各向异性和CS $ _2 $ COBR $ _4 $中几何挫败感之间竞争的指纹。
We have found an unusual competition of two frustration mechanisms in the 2D quantum antiferromagnet Cs$_2$CoBr$_4$. The key actors are the alternation of single-ion planar anisotropy direction of the individual magnetic Co$^{2+}$ ions, and their arrangement in a distorted triangular lattice structure. In particular, the uniquely oriented Ising-type anisotropy emerges from the competition of easy-plane ones, and for a magnetic field applied along this axis one finds a cascade of five ordered phases at low temperatures. Two of these phases feature magnetization plateaux. The low-field one is supposed to be a consequence of a collinear ground state stabilized by the anisotropy, while the other plateau bears characteristics of an "up-up-down" state exclusive for lattices with triangular exchange patterns. Such coexistence of the magnetization plateaux is a fingerprint of competition between the anisotropy and the geometric frustration in Cs$_2$CoBr$_4$.
