STSM of Máté Kedves at University of Basel (Switzerland)

The main aim of this short-term scientific mission was to fabricate and design ultra clean hBN-encapsulated graphene samples using superconducting electrodes making use of the experience and apparatus provided by the research group of Prof. Christian Schönenberger at the University of Basel. Our long term goal in combining graphene with superconductivity is to investigate topological excitations. To realize this, the coexistence of superconductivity and spin-orbit coupling is needed in ultra-clean graphene samples. With this motivation, during the STSM, we have fabricated several ultra clean encapsulated graphene samples. Part of them were used for an ongoing project of the Nanoelectronics group of the University of Basel to investigate the effects of proximity induced spin-orbit coupling in WSe2/BLG/hBN heterostructures. Joining this project enabled me to familiarise with the fabrication and measurement equipment, including the ultra-low temperature cryogenic system. Furthermore, we have fabricated simple hBN/G/hBN samples and we optimised the sputtering process of NbTiN and MoRe for contacting such samples, giving me the opportunity to better understand this thin-film deposition method. Moreover, due to the similarity of the sputtering equipment, most of this knowledge could be directly transferred to the home institute which gave a significant boost to the application of superconducting materials in graphene-based quantum electronic devices. Furthermore, for better comparison hBN/G/hBN samples were fabricated at the home institute and sent to the University of Basel for sputtering. Measurements on these samples and on the WSe2/BLG/hBN samples are currently being continued in Budapest.