Spin-Orbital Short-Range Order on a Honeycomb-Based Lattice
Spin-Orbital Short-Range Order on a Honeycomb-Based Lattice
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DOI：
10.1126/science.1212154
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发表时间：
2012-05-04
期刊：
影响因子：
56.9
通讯作者：
Broholm, C.
中科院分区：
文献类型：
--
作者：
Nakatsuji, S.;Kuga, K.;Broholm, C.
受抑磁性材料，其中能量最小化的局部条件是不相容的，因为晶格结构，可以保持无序的最低温度。Ba 3CuSb 2 O 9就是这种情况，它在原子尺度上是磁各向异性的，但在介观长度和时间尺度上是奇异的各向同性。我们发现，挫折的Wannier的伊辛模型上的三角形晶格是印在纳米结构的蜂窝晶格的Cu 2+离子，抵抗一个连贯的静态Jahn-Teller失真。由此产生的二维随机键自旋1/2系统上的蜂窝晶格具有广谱的自旋二聚体样激发和低能量自旋自由度，保持整体六边形对称。
Frustrated magnetic materials, in which local conditions for energy minimization are incompatible because of the lattice structure, can remain disordered to the lowest temperatures. Such is the case for Ba3CuSb2O9, which is magnetically anisotropic at the atomic scale but curiously isotropic on mesoscopic length and time scales. We find that the frustration of Wannier's Ising model on the triangular lattice is imprinted in a nanostructured honeycomb lattice of Cu2+ ions that resists a coherent static Jahn-Teller distortion. The resulting two-dimensional random-bond spin-1/2 system on the honeycomb lattice has a broad spectrum of spin-dimer-like excitations and low-energy spin degrees of freedom that retain overall hexagonal symmetry.