Zhang An-Lei, Gladilin Vladimir, Van de Vondel Joris, Moshchalkov Victor V, Ge Jun-Yi
Materials Genome Institute, Shanghai University, 200444 Shanghai, China.
TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen, Belgium.
Nano Lett. 2022 Sep 14;22(17):7151-7157. doi: 10.1021/acs.nanolett.2c02356. Epub 2022 Aug 18.
Flux quantization has been widely regarded as the hallmark of the macroscopic quantum state of superconductivity. However, practical design of superconductor devices exploiting finite size confinement effects may induce exotic phenomena, including nonquantized vortices. In our research, the magnetic flux of vortices has been studied in a series of superconducting strips as a function of the strip width and the penetration depth. In both circumstances, the observation using scanning Hall probe microscope (SHPM) displays a controlled evolution from singly quantized vortices to nonquantized ones. It is also found that the magnetic flux is immune to the flowing supercurrent. The simulations based on Ginzburg-Landau theory agree well with experimental results. The observed behavior of the vortex flux may open new perspectives for fundamental research and applications based on vortex matter, such as vortex-memory devices and magnetic field traps for ultracold atoms.
磁通量子化一直被广泛视为超导宏观量子态的标志。然而，利用有限尺寸限制效应的超导器件的实际设计可能会引发奇异现象，包括非量子化涡旋。在我们的研究中，已经在一系列超导条带中研究了涡旋的磁通量与条带宽度和穿透深度的函数关系。在这两种情况下，使用扫描霍尔探针显微镜（SHPM）的观察结果显示了从单量子化涡旋到非量子化涡旋的可控演化。还发现磁通量不受流动的超电流影响。基于金兹堡 - 朗道理论的模拟与实验结果吻合良好。观察到的涡旋通量行为可能为基于涡旋物质的基础研究和应用开辟新的前景，如涡旋存储器件和用于超冷原子的磁场陷阱。
