Extreme Suppression of Antiferromagnetic Order and Critical Scaling in a Two-Dimensional Random Quantum Magnet
Extreme Suppression of Antiferromagnetic Order and Critical Scaling in a Two-Dimensional Random Quantum Magnet
复制标题
二维随机量子磁体中反铁磁序的极端抑制和临界缩放，
DOI：
10.1103/physrevlett.126.037201
复制
发表时间：
2021-01-19
影响因子：
8.6
通讯作者：
Li, Shiliang
中科院分区：
文献类型：
--
作者：
Hong, Wenshan;Liu, Lu;Li, Shiliang
Sr_2CuTeO_6是一种正方晶格的N ' eel反铁磁体，它的第一近邻S = 1/2Cu自旋之间通过Te离子介导发生超交换。用W代替Te，受影响的杂质斑主要具有第二近邻相互作用，从而引起局部磁挫折。在这里，我们报告的研究Sr_2CuTe_（1-x）W_xO_6使用中子衍射和μ SR技术，表明N ' eel顺序已经消失在x = 0.025 +/- 0.005。我们使用二维海森堡自旋模型解释了这种极端的序抑制，证明了W型杂质引起了序参数的变形，在温度T = 0时随距离衰减为1/r（2）。相关的对数奇异性导致任何x > 0的阶数损失。小的x > 0和T > 0的阶是由弱的面间耦合引起的。在Sr 2CuTe 1-xWxO 6的超导相，μ SR弛豫速率表现出量子临界标度与一个大的动态指数，z近似为3，符合随机单重态。
Sr2CuTeO6 is a square-lattice N ' eel antiferromagnet with superexchange between first-neighbor S = 1/2 Cu spins mediated by plaquette centered Te ions. Substituting Te by W, the affected impurity plaquettes have predominantly second-neighbor interactions, thus causing local magnetic frustration. Here we report a study of Sr2CuTe1-xWxO6 using neutron diffraction and mu SR techniques, showing that the N ' eel order vanishes already at x = 0.025 +/- 0.005. We explain this extreme order suppression using a two-dimensional Heisenberg spin model, demonstrating that a W-type impurity induces a deformation of the order parameter that decays with distance as 1/r(2) at temperature T = 0. The associated logarithmic singularity leads to loss of order for any x > 0. Order for small x > 0 and T > 0 is induced by weak interplane couplings. In the nonmagnetic phase of Sr2CuTe1-xWxO6, the mu SR relaxation rate exhibits quantum critical scaling with a large dynamic exponent, z approximate to 3, consistent with a random-singlet state.