Department of Chemistry, 6-335, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Am Chem Soc. 2010 Nov 17;132(45):16185-90. doi: 10.1021/ja1070398. Epub 2010 Oct 22.
Structural characterization, exploiting X-ray scattering differences at elemental absorption edges, is developed to quantitatively determine crystallographic site-specific metal disorder. We apply this technique to the problem of Zn-Cu chemical disorder in ZnCu(3)(OH)(6)Cl(2). This geometrically frustrated kagomé antiferromagnet is one of the best candidates for a spin-liquid ground state, but chemical disorder has been suggested as a mundane explanation for its magnetic properties. Using anomalous scattering at the Zn and Cu edges, we determine that there is no Zn occupation of the intralayer Cu sites within the kagomé layer; however there is Cu present on the Zn intersite, leading to a structural formula of (Zn(0.85)Cu(0.15))Cu(3)(OH)(6)Cl(2). The lack of Zn mixing onto the kagomé lattice sites lends support to the idea that the electronic ground state in ZnCu(3)(OH)(6)Cl(2) and its relatives is nontrivial.
我们利用元素吸收边的 X 射线散射差异来进行结构特征分析，以定量确定晶体学位置特异性的金属无序。我们将这项技术应用于 ZnCu(3)(OH)(6)Cl(2)中 Zn-Cu 化学无序的问题。这种几何上受限制的 kagomé 反铁磁体是自旋液体基态的最佳候选者之一，但化学无序已被认为是其磁性的平凡解释。利用 Zn 和 Cu 边缘的反常散射，我们确定在 kagomé 层内没有 Zn 占据层内 Cu 位；然而，在 Zn 间位存在 Cu，导致结构公式为(Zn(0.85)Cu(0.15))Cu(3)(OH)(6)Cl(2)。Zn 没有混合到 kagomé 晶格位上，这支持了 ZnCu(3)(OH)(6)Cl(2)及其相关物的电子基态是非平凡的想法。
