氟化铜Cu $_2$ F $_5$是在$S=1$和$S=\frac{1}{2}$自旋状态中的Cu离子之间具有2D磁交换相互作用的化合物。利用从头计算方法,我们预测了Cu $_2$ F $_5$氟化物亚晶格中5%空位的存在导致了所有铜离子自旋态的剧烈转变,最终自旋态为$S=\frac{1}{2}$和$S=0$ .因此,磁相互作用的各向异性增加,并且出现Cu $d^9$、$S=\frac{1}{2}$离子的一维线性链。我们还提出了一个微观机制,通过CuO $_6$八面体的延伸,这种交换相互作用的转变。
英文摘要:
The copper fluoride Cu$_2$F$_5$ is a compound with 2D-magnetic exchange interactions between the Cu ions in the $S=1$ and $S=\frac{1}{2}$ spin-states. Using ab-initio calculations, we predict that the existence of 5% vacancies in the fluoride sublattice of Cu$_2$F$_5$ results in the drastic transformation of the spin-state of all copper ions and the final spin-states are $S=\frac{1}{2}$ and $S=0$. Consequently, the anisotropy of magnetic interactions increases, and the 1D linear chains of the Cu $d^9$, $S=\frac{1}{2}$ ions appear. We also propose a microscopic mechanism of such exchange interaction transformation via CuO$_6$ octahedra elongation.
Differentiation of electron doping and oxygen reduction in electron-doped cuprates
Institute for Solid State Physics, The University of Tokyo(东京大学固体离子体研究所);Department of Engineering and Applied Sciences, Sophia University(上智大学理工学部);Department of Applied Physics, Tohoku University(东北大学应用物理系);UVSOR Synchrotron Facility, Institute for Molecular Science(分子科学研究所UVSOR同步辐射设施)
From perovskite to infinite-layer nickelates: hole concentration from x-ray absorption
Max Planck Institute for Solid State Research(马克斯·普朗克固体研究所);Universite de Strasbourg, CNRS, IPCMS UMR 7504(斯特拉斯堡大学);Helmholtz-Zentrum Berlin für Materialien und Energie(柏林亥姆霍兹材料与能源中心);European Synchrotron Radiation Facility(欧洲同步辐射装置);Karlsruhe Institute of Technology (KIT)(卡尔斯鲁厄理工学院)
Finite-size effects in the quasi-one-dimensional quantum magnets Sr$_{2}$CuO$_{3}$, Sr$_{2}$Cu$_{0.99}$M$_{0.01}$O$_{3}$ (M = Ni, Zn), and SrCuO$_{2}$
研究了准一维自旋S = $\frac{1}{2}$海森堡反铁磁体Sr $_{2}$ CuO $_{3}$,Sr $_{2}$ Cu $_{0.99}$ M $_{0.01}$ O $_{3}$(M = Zn和Ni)和SrCuO $_{2}$的磁性的有限尺寸效应.磁化率数据进行了分析,以估计浓度的链断裂由于extraminated缺陷和/或由于轻微的氧非化学计量。我们发现,Sr $_{2}$ Cu $_{0.99}$ Ni $_{0.01}$ O $_{3}$的磁化率可以通过考虑Ni $^{2+}$作为一个标量缺陷($S_{eff}=0$),表明Ni自旋被屏蔽。在Sr $_{2}$ Cu $_{0.99}$ Zn $_{0.01}$ O $_{3}$磁化率分析产生的缺陷浓度小于标称值,这是在良好的定性与晶体生长实验。研究了掺杂对低温长程自旋有序态的影响。在化合物SrCuO $_{2}$中,由Z字形S = $\frac{1}{2}$链组成,讨论了自旋阻挫对磁有序和由磁化率数据确定的缺陷浓度的影响。