Department of Physics and the Institute of Materials Research, Pennsylvania State University, University Park, PA 16802, USA.
Proc Natl Acad Sci U S A. 2012 Sep 11;109(37):14819-23. doi: 10.1073/pnas.1200664109. Epub 2012 Aug 27.
The destruction of superconducting phase coherence by quantum fluctuations and the control of these fluctuations are a problem of long-standing interest, with recent impetus provided by the relevance of these issues to the pursuit of high temperature superconductivity. Building on the work of Little and Parks, de Gennes predicted more than three decades ago that superconductivity could be destroyed near half-integer-flux quanta in ultrasmall loops, resulting in a destructive regime, and restored by adding a superconducting side branch, which does not affect the flux quantization condition. We report the experimental observation of this Little-Parks-de Gennes effect in Al loops prepared by advanced e-beam lithography. We show that the effect can be used to restore the lost phase coherence by employing side branches.
超导相位相干性被量子涨落破坏以及对这些涨落的控制是一个由来已久的问题，最近由于这些问题与高温超导的研究有关而受到关注。基于 Little 和 Parks 的工作，de Gennes 在三十多年前就预测，在超小环中的半整数磁通量子附近，超导性可能会被破坏，从而导致一个破坏状态，并通过添加一个不影响磁通量子化条件的超导侧支来恢复。我们通过先进的电子束光刻制备的 Al 环实验观察到了这种 Little-Parks-de Gennes 效应。我们表明，可以通过使用侧支来恢复丢失的相位相干性。
