Fluctuations in superconducting rings with two order parameters
Fluctuations in superconducting rings with two order parameters
复制标题
DOI：
10.1103/physrevb.84.214515
复制
发表时间：
2011-05
影响因子：
3.7
通讯作者：
J. Berger;M. Milovsevi'c
中科院分区：
文献类型：
--
作者：
J. Berger;M. Milovsevi'c
本文从Ginzburg-Landau能量泛函出发，讨论了两个序参量的存在以及它们之间的耦合对涨落区超导环的影响。我们的方法是精确的，但需要数值实现。我们还研究了近似，可以得到一些解析表达式，并检查其有效性范围。我们提供的温度范围内的波动是重要的估计，计算的持续电流在二硼化镁环作为温度和封闭通量的函数，并指出其额外的依赖环的横截面积。我们发现温度区域中的波动增强持续电流和区域中，他们抑制持续电流。存在两个可以独立波动的序参数总是导致在Tc处的序参数的较大平均值，但仅对于适当的参数，这产生较大的持续电流。在非常不同的材料参数的情况下，两个耦合的冷凝物，持续电流被抑制。
Starting from the Ginzburg-Landau energy functional, we discuss how the presence of two order parameters and the coupling between them influence a superconducting ring in the fluctuative regime. Our method is exact, but requires numerical implementation. We also study approximations for which some analytic expressions can be obtained, and check their ranges of validity. We provide estimates for the temperature ranges where fluctuations are important, calculate the persistent current in magnesium diboride rings as a function of temperature and enclosed flux, and point out its additional dependence on the cross-section area of the ring. We find temperature regions in which fluctuations enhance the persistent currents and regions where they inhibit the persistent current. The presence of two order parameters that can fluctuate independently always leads to larger averages of the order parameters at Tc, but only for appropriate parameters this yields larger persistent current. In cases of very different material parameters for the two coupled condensates, the persistent current is inhibited.