Enhancement of the critical temperature in iron pnictide superconductors by finite-size effects
Enhancement of the critical temperature in iron pnictide superconductors by finite-size effects
复制标题
DOI：
10.1103/physrevb.84.172502
复制
发表时间：
2011-03
影响因子：
3.7
通讯作者：
M. A. N. Ara'ujo;Antonio M. Garc'ia-Garc'ia-Antonio-M.-Garc'ia-Garc'ia-1397392420;P. Sacramento
中科院分区：
文献类型：
--
作者：
M. A. N. Ara'ujo;Antonio M. Garc'ia-Garc'ia-Antonio-M.-Garc'ia-Garc'ia-1397392420;P. Sacramento
最近的实验表明，与先前的理论预测一致，金属纳米结构中的超导性可以在体积限制方面得到增强。在这些结果的激励下，我们研究了铁镍超导体中的有限尺寸效应。对于体临界温度Tc ~ 20 ~ 50k的实际值，我们发现，在纳米尺度区域L ~ 10 nm， Tc(L)具有复杂的振荡模式，作为系统尺寸L的函数。在不同的边界条件、几何形状和两种超导微观模型下，Tc相对于体极限有明显的增强。打破长程秩序的热波动在这个地区仍然很小。最后，我们表明，差分电导，一个实验观察，也是非常敏感的FSE。
Recent experiments have shown that, in agreement with previous theoretical predictions, superconductivity in metallic nanostructures can be enhanced with respect to the bulk limit. Motivated by these results we study finite size effects (FSE) in an iron-pnictide superconductor. For realistic values of the bulk critical temperature Tc ~ 20-50K, we find that, in the nanoscale region L ~ 10 nm, Tc(L) has a complicated oscillating pattern as a function of the system size L. A substantial enhancement of Tc with respect to the bulk limit is observed for different boundary conditions, geometries and two microscopic models of superconductivity. Thermal fluctuations, which break long range order, are still small in this region. Finally we show that the differential conductance, an experimental observable, is also very sensitive to FSE.