Vakaryuk Victor
Department of Physics, University of Illinois, Urbana, IL 61801, USA.
Phys Rev Lett. 2008 Oct 17;101(16):167002. doi: 10.1103/PhysRevLett.101.167002. Epub 2008 Oct 14.
A universal mechanism of restoration of minimal hc/e periodicity in the response of small superconducting rings or cylinders to the magnetic flux is proposed. The mechanism is based on the dependence of the Cooper pair's internal energy on its motion as a whole and does not rely on the presence of quasiparticles in the system. The thermal equilibrium hc/2e periodicity is broken by an offset of the transition between different current-carrying states. The magnitude of the offset is calculated for an s-wave superconducting cylinder of radius R in the limit R>>xi_{0}, where xi_{0} is the BCS coherence length and turns out to be exponentially small. A possible enhancement of the effect for nodal superconductors is suggested. Similar conclusions should also apply to the response of charged or neutral superfluids to rotation.
提出了一种关于小超导环或圆柱体对磁通量响应中最小hc/e周期性恢复的通用机制。该机制基于库珀对的内能对其整体运动的依赖性，并且不依赖于系统中准粒子的存在。不同载流状态之间跃迁的偏移打破了热平衡hc/2e周期性。对于半径R>>xi₀的s波超导圆柱体，计算了偏移量，其中xi₀是BCS相干长度，结果发现其呈指数级小。有人提出了节点超导体效应可能增强的情况。类似的结论也应适用于带电或中性超流体对旋转的响应。
