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。
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 E_F 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 T_c and △_0 are obtained. The results show thatbotk the interlnolecular low-frequency modes and the intramolecular high frequencymodes participate the electron-phonon interactions,T_c 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/k_BT_c.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1994年第7期1159-1165,共7页
Acta Physica Sinica
基金
国家自然科学基金
浙江省自然科学基金
