STSM of Celia González (UAM, Spain) at The Hebrew University of Jerusalem (Israel)

The aim of this short-term scientific mission (STSM) was to advance the fabrication of high-quality van der Waals heterostructure (vdW) devices for the investigation of the electronic properties of novel hybrid superconducting systems based on 2D materials. Specifically, we were interested in preparing tunnel junctions comprised of 2D superconductors, e.g., NbSe2, and TMD tunnel barriers, such as MoS2, WSe2 etc., for studying the density of states (DOS) of a 2D superconductor in proximity to magnetic materials. With this STSM, we intended to benefit from the infrastructure for the preparation of vdW heterostructures in inert atmospheres of the host research group of Dr. Hadar Steinberg at the Hebrew University of Jerusalem in Israel, as well as from their know-how related to NbSe2 to fabricate 2D tunnel junctions.

During the STSM, six 2D Josephson junction devices were fabricated using the dry pick-up and transfer technique, in which NbSe2 is used for the superconducting electrodes and two TMDs, MoS2 and WSe2, as the weak links.

Preliminary electrical transport measurements demonstrate an excellent performance of the devices. Furthermore, we plan to measure the devices in our low temperature setup in Spain and compare the behaviour of this combination of materials in a vertical Josephson junction geometry to our previous measurements of SC/antiferromagnet/SC vertical JJs systems.

Since the sample fabrication process has been successful, we plan to study these hybrid superconducting systems in collaboration with Prof. Steinberg’s group. This will hopefully provide new insights into these combinations of materials in a Josephson junction geometry, which have not yet been reported in literature.