Experimental Physics of Nanostructured Materials, Q-MAT, CESAM, Université de Liège, B-4000 Sart Tilman, Belgium.
Nanoscale. 2018 Jan 25;10(4):1987-1996. doi: 10.1039/c7nr08571k.
We demonstrate the in situ engineering of superconducting nanocircuitry by targeted modulation of material properties through high applied current densities. We show that the sequential repetition of such customized electro-annealing in a niobium (Nb) nanoconstriction can broadly tune the superconducting critical temperature T and the normal-state resistance R in the targeted area. Once a sizable R is reached, clear magneto-resistance oscillations are detected along with a Fraunhofer-like field dependence of the critical current, indicating the formation of a weak link but with further adjustable characteristics. Advanced Ginzburg-Landau simulations fully corroborate this picture, employing the detailed parametrization from the electrical characterization and high resolution electron microscope images of the region within the constriction where the material has undergone amorphization by electro-annealing.
我们通过施加高电流密度来有针对性地调节材料特性，从而实现了超导纳米电路的原位工程。我们表明，在铌（Nb）纳米限制中重复进行这种定制的电退火，可以广泛调节目标区域的超导临界温度 T 和正常态电阻 R。一旦达到相当大的 R 值，就会检测到明显的磁电阻振荡，以及临界电流的类似夫琅和费的场依赖性，这表明形成了一个弱连接，但具有进一步可调特性。先进的吉布斯-朗道模拟完全证实了这一图景，该模拟采用了来自电退火使材料非晶化的限制区域的详细参数化，以及高分辨率电子显微镜图像的电特性。
