期刊：
International Journal of Modern Physics B,2003年17(27):4841-4857 ISSN：0217-9792
通讯作者：
Mei, T
作者机构：
[Mei, T] Cent China Normal Univ, Editorial Dept Journal, Wuhan, Hubei, Peoples R China.
通讯机构：
[Mei, T] C;Cent China Normal Univ, Editorial Dept Journal, Wuhan, Hubei, Peoples R China.
关键词：
Tunneling effect;Cooper pairs;weak-link superconductor;multi-junctions;overstepping Josephson approximation;exact solution;elliptic function
摘要：
In this paper, tunneling effect of Cooper pairs in weak-link superconductor structure with multi-junctions under the condition for overstepping the Josephson approximation is discussed. The equations describing the electric current based on the tunneling effect of Cooper pairs in several kinds of weak-link superconductor structures with multi-junctions are obtained under the condition to overstep the Josephson approximation. For both SISISIS and a four junctions ring, when all junctions are in the zero voltage state, the exact solution of the equations is obtained. It is found that, because of the tunneling effect of the Cooper pairs, an alternating current exists which can be expressed by an elliptic function. For a four junctions ring, the relation between the period of the alternating current and flux is pointed out. At last, the condition for overstepping the Josephson approximation is discussed. The result shows that overstepping the Josephson approximation may be possible when the volumes of superconductors are small enough.
期刊：
International Journal of Modern Physics B,2002年16(24):3697-3705 ISSN：0217-9792
通讯作者：
Mei, T
作者机构：
[Mei, T] Cent China Normal Univ, Editorial Dept Journal, Wuhan, Hubei PRO, Peoples R China.
通讯机构：
[Mei, T] C;Cent China Normal Univ, Editorial Dept Journal, Wuhan, Hubei PRO, Peoples R China.
摘要：
The tunneling effect of the Cooper pairs in a superconductor-insulator-superconductor-insulator-superconductor structure is analyzed by Feynman-like method, and the equations describing the electric current are obtained. For the case when both junctions are in the zero voltage state, the exact solution of the equations is obtained. It is found that, because of the tunneling effect of the Cooper pairs, an alternating current exists which can be expressed by an elliptic function. And then, on second thoughts, the conclusion that the SISIS cannot emit electromagnetic radiation when both junctions are in the zero voltage state, though an alternating current exists, is pointed out.
