标题： 紧密束缚库珀对超导体中阿布里科索夫涡旋核心外的超导性增强 显示英文标题

标题： Enhancement of superconductivity outside Abrikosov vortex core in a tightly bound Cooper pair superconductor

摘要： 阿布里科索夫涡旋在II型超导体中破坏超导性中起着核心作用。 人们普遍认为，当远离$s$波超导体的涡旋轴时，超导电子的密度从零逐渐增加到其体值。 然而，我们证明，如果组成超导液体的库珀对结合得足够紧密，在零温极限下，这种行为会发生定性变化。 具体而言，在涡旋核心之外，超导电子的密度达到一个超过其体值的最大值。 这一现象具有静电起源：由于正常电子不存在，并且存在带电的离子背景，超导电子的电荷密度的空间变化会破坏局部电中性，导致电场的产生。 这个电场收缩了涡旋核心，并将密度分布转变为具有最大值的形式，确保全局电中性。 在强静电屏蔽极限下，这一效应最为显著，此时描述涡旋的场配置呈现出一种普遍形式，电场在由伦敦穿透深度决定的长度尺度上被屏蔽。 显示英文摘要

摘要： Abrikosov vortices play a central role in the disruption of superconductivity in type-II superconductors. It is commonly accepted that as one moves away from the vortex's axis of an $s$-wave superconductor, the density of superconductive electrons gradually increases from zero to its bulk value. However, we demonstrate that this behavior is qualitatively altered in the zero-temperature limit provided that the Cooper pairs comprising the superconductive liquid are sufficiently tightly bound. Specifically, outside the vortex core, the density of superconductive electrons reaches a maximum surpassing its bulk value. This phenomenon has electrostatic origins: since normal electrons are absent and there exists a charged ionic background, the spatial variation of the charge density of superconductive electrons violates local neutrality, leading to the generation of an electric field. This electric field shrinks the vortex core and turns the density profile into that with a maximum, ensuring global neutrality. The effect is most pronounced in the limit of strong electrostatic screening, where the field configurations describing the vortex attain a universal form, with the electric field screened over a length scale determined by the London penetration depth.