Authors: Mohammad T. Haque, MarcoWill, MattiTomi, Preeti Pandey, Manohar Kumar, Felix Schmidt, Kenji Watanabe, TakashiTaniguchi, Romain Danneau, Gary Steele and Pertti Hakonen
Scientific Reports volume 11, Article number: 19900 (2021)
Abstract: We have studied 1/f noise in critical current 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 nA. The low frequency noise in the superconducting state is measured by tracking the variation in magnitude and phase of a reflection carrier signal at 600–650 MHz. We find 1/f critical current fluctuations on the order of per unit band at 1 Hz. The noise power spectrum of critical current fluctuations measured near the Dirac point at large, sub-critical rf-carrier amplitudes obeys the law where and at Hz. Our results point towards significant fluctuations in originating from variation of the proximity induced gap in the graphene junction.