Periodic hole structure in a spin-chain ladder material Sr 14 Cu 24 O 41
Periodic hole structure in a spin-chain ladder material Sr 14 Cu 24 O 41
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自旋链梯材料Sr 14 Cu 24 O 41 中的周期性空穴结构
DOI：
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发表时间：
2002
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通讯作者：
M. Matsuda
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作者：
T. Fukuda;J. Mizuki;M. Matsuda
对 ${mathrm{Sr}}_{14}{mathrm{Cu}}_{24}{mathrm{O}}_{41},$ 的单晶进行了高能同步加速器 X 射线衍射测量，该单晶据报道具有不同的磁性和结构相关性，以研究其起源 差异更准确。在低温下，我们在 $Q=(0,0,2nifmmodepmelse extpmfi{}{1/5)}_{c},$ 处观察到弱超晶格峰，而在 $Q=(0,0,2nifmmodepmelse extpmfi{}{1/4)}_{c},$ 处没有发现任何东西，这在之前的 X 射线工作中报告过 考克斯等人。 [物理。修订版 B 57, 10 750 (1998)]。因此，沿着c（ensuremath{Vert}链轴）方向，晶格畸变不是链结构周期性的4倍而是5倍。这些卫星峰的强度随着温度的升高而降低。这些观察结果根据空穴排序模型得到了正确的解释，该模型涉及${mathrm{CuO}}_{2}$链中Zhang-Rice单线态位点上两个${mathrm{Cu}}^{2+}$离子和${mathrm{Cu}}^{3+}$离子的二聚态。使用高能 X 射线 ${(E}_{i}ensuremath{simeq}53.789 mathrm{keV}),$ 可以清楚地观察到这些特征，而在低能 X 射线实验中，只需很少的样品表面处理，超晶格峰值强度就会发生巨大变化 ${(E}_{i}ensuremath{simeq}15.498 mathrm{keV}).$
High-energy synchrotron x-ray diffraction measurements were carried out on a single crystal of ${mathrm{Sr}}_{14}{mathrm{Cu}}_{24}{mathrm{O}}_{41},$ which had been reported to have different magnetic and structural correlations, in order to investigate the origin of this discrepancy more precisely. At low temperature, we observed weak superlattice peaks at $Q=(0,0,2nifmmodepmelse extpmfi{}{1/5)}_{c},$ while nothing was found at $Q=(0,0,2nifmmodepmelse extpmfi{}{1/4)}_{c},$ which was reported in a previous x-ray work by Cox et al. [Phys. Rev. B 57, 10 750 (1998)]. Therefore, the lattice distortion has not 4 but 5 times the periodicity of the chain structure along c (ensuremath{Vert} chain axis) direction. These satellite peaks decreased in intensity with increasing temperature. These observations were interpreted properly in terms of a hole ordering model involving the dimerized state of two ${mathrm{Cu}}^{2+}$ ions and a ${mathrm{Cu}}^{3+}$ ion on a Zhang-Rice singlet site in the ${mathrm{CuO}}_{2}$ chains. These features were clearly observed by using high-energy x rays ${(E}_{i}ensuremath{simeq}53.789 mathrm{keV}),$ while the superlattice peak intensity varied drastically with very little sample surface treatment in the case of low-energy x-ray experiments ${(E}_{i}ensuremath{simeq}15.498 mathrm{keV}).$