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碱金属掺杂富勒烯超导体的临界温度和约化能隙研究
THEORY OF SUPERCONDUCTIVITY IN ALDALI一METAL - DOPED FULLERENES
【摘要】 碱金属掺杂富勒烯与传统的超导体情况不同,它有一个很宽区域的声子谱,其最高频率和最低频率分别与费密能E_F和零温超导能隙△_0为同一数量级,这必将导致对原来强耦合超导电性理论的修正。本文在此情况下求解Eliashberg方程,得到T_c和△_0的表达式。结果表明,分子间的低频振动模和分子上的高频振动模同样参与电声耦合,T_c主要取决于声子谱中高频成份的贡献,而△_0的增加主要取决于声子谱中低频成份的贡献,这样,可以统一地解释实验结果,特别是远大于原来理论值的2△_0/k_BT_c。
【Abstract】 It is different from the case of conventional superconductors that th alkali-metal-doped fullerenes Lave wide-frequency-range phonon spectra whose high-and low-fre-quency phonon modes are, respectively,comparable to the Fermi energy EF and thezero-temperature gap △0.Tkis property will lead to a modification to the theory ofconventional strong coupling superconductivity.In this paper, by solving the Eliash。berg equations,the expressions of Tc and △0 are obtained. The results show thatbotk the interlnolecular low-frequency modes and the intramolecular high frequencymodes participate the electron-phonon interactions,Tc mainly arise from the high-frequency modes while △0’s enhancement mainly arise from the low-frequency modes。So, the experimental results can be explained,especially,the large ratio of 2△0/kBTc.
- 【文献出处】 物理学报 ,ACTA PHYSICA SINICA , 编辑部邮箱 ,1994年07期
- 【分类号】O511.1
- 【被引频次】1
- 【下载频次】151