EMP is funded through the Horizon2020 programme of the European Commission.
Selected Publications

Critical current fluctuations in graphene Josephson junctions

Mohammad T. Haque, Marco Will, Matti Tomi, Preeti Pandey, Manohar Kumar, Felix Schmidt, Kenji Watanabe, Takashi Taniguchi, Romain Danneau, Gary Steele, Pertti Hakonen

We have studied 1/f noise in critical current Ic in h-BN encapsulated monolayer graphene contacted by NbTiN electrodes. The sample is close to diffusive limit and the switching supercurrent with hysteresis at Dirac point amounts to ≃5 nA. The low frequency noise in the superconducting state is measured by tracking the variation in magnitude and phase of a reflection carrier signal vrf at 600–650 MHz. We find 1/f critical current fluctuations on the order of δIc/Ic≃1E−3 per unit band at 1 Hz. The noise power spectrum of critical current fluctuations SIc measured near the Dirac point at large, sub-critical rf-carrier amplitudes obeys the law SIc/Ic2=a/fβ where a≃4E−6 and β≃1 at f>0.1 Hz. Our results point towards significant fluctuations in Ic originating from variation of the proximity induced gap in the graphene junction.

Sci Rep 11, 19900 (2021)

doi: 10.1038/s41598-021-99398-3