QDev Seminar: Michaela Eichinger – University of Copenhagen

Michaela Eichinger

Research Group Prof Dr Christoph Strunk, University of Regensburg, Regensburg, Germany

Quantum transport through carbon nanotube NbSe2 hybrid devices

The initial proposals for the realization of Majorana fermions (MFs) were based on one- dimensional semiconductors proximitized by a superconductor in the presence of spin-orbit interaction and of perpendicular magnetic field. More recently, it was suggested that MFs can also occur in carbon nanotubes (CNTs) in proximity to an ultrathin superconductor in large parallel fields [1]. In this work, the first building blocks of the device proposed by Marganska et al are demonstrated. As a superconductor we chose a bilayer NbSe2 crystal, which is so thin that its electron density and chemical potential can be tuned by a gate. Additionally we present the implementation of edge contacts to the CNT and NbSe2 allowing contact resistances in the few hundred Ω/ low kΩ range. Finally, a carbon nanotube NbSe2 hybrid device for the detection of quantum phase slip lines is presented, whose characteristics are measured as a function of temperature.

[1] M. Marganska et al. Phys. Rev. B 97, 075141 (2018)