Knowledge of solid state physics, motivation for experimental work, English knowledge, basic programming and measurement automation experience.
Recently a very interesting effect was experimentally observed that the supercurrent can be switched off by applying voltage on a neighboring gate electrode in superconducting nanobridges. In the literature there is no consensus on the microscopic origin: either novel exotic electric field induced frustration of the superconducting state or leakage current induced fluctuation are the proposed mechanisms.
We plan to carry out different novel experiments to investigate this question in epitaxial superconducting layers grown on the surface of an InAs nanowire.
We will study in detail superconducting switching current distributions, which based on our preliminary results is a useful measurable quantity to learn about the fluctuations in the system. We will particularly focus on the time scale of the fluctuations in these experiments.
Another important parameter is the level of the leakage current in these devices, which we plan to vary by using different substrates, like saphere. Towards application it is also important to demonstrate elementary logic circuits based on supra gating, thus we plan to design, realize and measure such nanocircuits as well, in order to address the limitation on scaling-up.