论文标题
暂时增强了磁场的超导性
Temporarily enhanced superconductivity from magnetic fields
论文作者
论文摘要
与在应用磁场时对超导性的预期有害影响相反，我们预测这种场的突然发作可以暂时增强超导级参数。具体而言，我们发现以正常金属弱连接的约瑟夫森交界处的超电流可以以这种方式增加20倍以上。可以从Andreev反射的能量依赖性与系统中激发的分布函数中突然的自旋依赖性转移之间的相互作用来理解效果。增加的持续时间取决于系统中的非弹性散射率，估计在纳秒范围内。我们通过开发一种解决USADEL方程的方法来证明这一点，以实现任意时间依赖性。这使得在将超导体与不同类型的材料结合的异质结构中的超快时间相关物理学进行了研究。
Contrary to the expected detrimental influence on superconductivity when applying a magnetic field, we predict that the abrupt onset of such a field can temporarily strongly enhance the superconducting order parameter. Specifically, we find that the supercurrent in a Josephson junction with a normal metal weak link can increase more than twentyfold in this way. The effect can be understood from the interplay between the energy-dependence of Andreev reflection and the abrupt spin-dependent shift in the distribution functions for excitations in the system. The duration of the increase depends on the inelastic scattering rate in the system and is estimated to be in the range of nanoseconds. We demonstrate this by developing a method which solves the Usadel equation for an arbitrary time-dependence. This enables the study of ultrafast time-dependent physics in heterostructures combining superconductors with different types of materials.
