13C NMR Spectroscopy of KxC60: Phase Separation, Molecular Dynamics, and Metallic Properties
13C NMR Spectroscopy of KxC60: Phase Separation, Molecular Dynamics, and Metallic Properties
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KxC60 的 13C NMR 光谱：相分离、分子动力学和金属性质
DOI：
10.1126/science.253.5022.884
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发表时间：
1991
期刊：
影响因子：
56.9
通讯作者：
John C. Tully
中科院分区：
文献类型：
--
作者：
R. Tycko;G. Dabbagh;M. Rosseinsky;D. W. Murphy;R. Fleming;A. P. Ramirez;John C. Tully
报道了碱金属富勒烯 KxC60 的 13C 核磁共振 (NMR) 测量结果。 NMR 谱表明，0 < x < 3 的材料实际上是处于平衡状态的两相系统，其中 x = 0 和 x = 3。NMR 线形表明，C3-60 离子在 300 K 下在 K3C60 相中快速旋转，而绝缘 K6C60 相中的 C6-60 离子在线形测量的时间尺度上是静态的。发现 K3C60 正常状态下 13C 自旋晶格弛豫速率的温度依赖性是金属的特征，表明 C3-60 离子在电导率中的重要作用。根据弛豫测量，可以得出费米能级电子态密度的估计值。
The results of 13C nuclear magnetic resonance (NMR) measurements on alkali fullerides KxC60 are reported. The NMR spectra demonstrate that material with 0 < x < 3 is in fact a two-phase system at equilibrium, with x = 0 and x = 3. NMR lineshapes indicate that C3–60 ions rotate rapidly in the K3C60 phase at 300 K, while C6–60 ions in the insulating K6C60 phase are static on the time scale of the lineshape measurement. The temperature dependence of the 13C spin-lattice relaxation rate in the normal state of K3C60 is found to be characteristic of a metal, indicating the important role of the C3–60 ions in the conductivity. From the relaxation measurements, an estimate of the density of electronic states at the Fermi level is derived.