Raman scattering in calcium-doped C-60
Raman scattering in calcium-doped C-60
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DOI：
10.1103/physrevb.54.3971
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发表时间：
1996-08-01
影响因子：
3.7
通讯作者：
Roth, S
中科院分区：
文献类型：
--
作者：
Chen, XH;Zhou, XJ;Roth, S
给出并讨论了CaxC60(x=3，5)的室温拉曼散射光谱的实验结果。与碱金属掺杂的C-60类似，与切向振动模式相关的高频谱线相对于它们在C-60中的位置发生了下移。相反，随着钙离子浓度的增加，径向银模的低频谱线强烈地向高频方向移动。对于相同的电荷转移，这种上移量比碱掺杂的C-60的上移量大得多。这一行为表明，径向银模强烈依赖于掺杂金属，C-60分子与周围金属离子之间存在着很强的相互作用。在超导Ca5C60中，由于大量的电子-声子耦合，观察到了汞(7)和汞(8)模的强烈衰减。
Experimental results on Raman-scattering spectra of CaxC60 (x=3,5) taken at room temperature are presented and discussed. The high-frequency lines associated with the tangential vibrational modes are observed to down-shift relative to their position in C-60, which is similar to that of alkali-metal-doped C-60 In contrast, the low-frequency line of the radial Ag mode strongly shifts to higher frequencies with increasing calcium concentrations. This upshift is much larger than that of alkali-doped C-60 for the same charge transfer. This behavior indicates that the radial Ag mode is strongly dependent on the doping metal and that there exists a strong interaction between the C-60 molecule and the surrounding metal ions. In superconducting Ca5C60, a strong damping of Hg(7) and Hg(8) modes is observed due to substantial electron-phonon coupling.