We successfully produce Josephson junctions by stacking NbSe2 flakes, where the twist angle and strain are responsible for a weak link. Field sweep measurements are taken to characterize these...Show moreWe successfully produce Josephson junctions by stacking NbSe2 flakes, where the twist angle and strain are responsible for a weak link. Field sweep measurements are taken to characterize these devices. These measurements highlight the importance of the direction of the applied magnetic field. Prompted by this, simulations of the critical current given an arbitrarily shaped interface area are presented and compared to measurements.Show less
Majorana quasiparticles can arise at the ends of one dimensional superconducting quantum wires. As a true one-dimensional experimental realization of such a quantum wire, a carbon nanotube can be...Show moreMajorana quasiparticles can arise at the ends of one dimensional superconducting quantum wires. As a true one-dimensional experimental realization of such a quantum wire, a carbon nanotube can be employed. The one-dimensional carbon nanotube can inherit the superconducting properties by bringing it in close contact to a superconductor, such as van der Waals superconductor niobium diselenide. In this work, the design and fabrication of devices are discussed that contain a carbon nanotube connected to a few atomic layer thick niobium diselenide. Bi- or trilayers of niobium diselenide crystal flakes are obtained using mechanical exfoliation techniques in inert conditions. A stamping resolution of about 1 mm is obtained in positioning the flakes with respect to each other which is shown by Atomic Force Microscopy. Initial characterizations have shown an improvement of the conductance of more than two orders of magnitude. The stability diagrams, however, exhibit a complex behaviour which we were unable to explain in terms of a proximitized carbon nanotube. We have shown that it is possible to fabricate the complete hybrid device that is predicted to host Majorana Fermions in its non-trivial phase. This work was conducted at Regensburg University in the group of Professor Christoph Strunk.Show less
