arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2001.09881cond-mat.str-elcond-mat.other
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准二维蜂窝状化合物InCu $_{2/3}$ V $_{1/3}$ O $_3$的基态和低温磁性

Ground state and low-temperature magnetism of the quasi-two-dimensional honeycomb compound InCu$_{2/3}$V$_{1/3}$O$_3$

M. Iakovleva, O. Janson, H. -J. Grafe, A. P. Dioguardi, H. Maeter, N. Yeche, H. -H. Klauss, G. Pascua, H. Luetkens, A. Moeller, B. Buechner, V. Kataev, E. Vavilova

摘要:

我们报告了一个组合的$^{115}$在NQR,$^{51}$ V NMR和$μ$ SR光谱研究的低温磁性的InCu $_{2/3}$ V $_{1/3}$ O $_3$,准二维(2D)化合物,包括在自旋扇区的反铁磁耦合自旋$S=1/2$蜂窝晶格与铜$^{2+}$离子。尽管大量的实验和理论的努力,这种材料的基态是没有最终确定。特别是,在不同的磁测量中表现为异常的两个特征温度约为$\sim 40$ K和$\sim 20$ K,本文对此进行了有争议的讨论。对实验数据的综合分析与交换常数的理论计算相结合,使我们能够在39 K以下识别出“中间”准二维静态自旋态。这种自旋状态的特点是交错磁化与温度演化,同意的2D XY模型的预测。我们观察到,该状态在15 K时逐渐转变为完全发展的3D反铁磁Néel状态。我们归因于这样一个扩展的准2D静态制度的蜂窝状平面的有效的磁去耦由于层间交换相互作用,抑制长距离自旋-自旋相关的平面之间的强烈挫折。有趣的是,我们发现的拓扑Berezinsky-Kosterlitz-无相变的迹象在准二维静态的蜂窝自旋1/2平面的InCu $_{2/3}$ V $_{1/3}$ O $_3$。

英文摘要:

We report a combined $^{115}$In NQR, $^{51}$V NMR and $μ$SR spectroscopic study of the low-temperature magnetic properties of InCu$_{2/3}$V$_{1/3}$O$_3$, a quasi-two dimensional (2D) compound comprising in the spin sector a honeycomb lattice of antiferromagnetically coupled spins $S=1/2$ associated with Cu$^{2+}$ ions. Despite substantial experimental and theoretical efforts, the ground state of this material was has not been ultimately identified. In particular, two characteristic temperatures of about $\sim 40$ K and $\sim 20$ K manifesting themselves as anomalies in different magnetic measurements are discussed controversially. A combined analysis of the experimental data complemented with theoretical calculations of exchange constants enabled us to identify below 39 K an ``intermediate'' quasi-2D static spin state. This spin state is characterized by a staggered magnetization with a temperature evolution that agrees with the predictions for the 2D XY model. We observe that this state gradually transforms at 15 K into a fully developed 3D antiferromagnetic Néel state. We ascribe such an extended quasi-2D static regime to an effective magnetic decoupling of the honeycomb planes due to a strong frustration of the interlayer exchange interactions which inhibits long-range spin-spin correlations across the planes. Interestingly, we find indications of the topological Berezinsky-Kosterlitz-Thouless transition in the quasi-2D static state of the honeycomb spin-1/2 planes of InCu$_{2/3}$V$_{1/3}$O$_3$.

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