Effect of high-frequency electrodynamic environment on the single-electron tunneling in ultrasmall junctions

Abstract

Single-electron tunneling in Al/${\mathrm{AlO}}_{\mathrm{x}}$/Al junctions with areas below 0.01 \ensuremath{\mu}${\mathrm{m}}^{2}$ was studied at temperatures close to 1 K. The junctions, placed in different high-frequency environments but similar in all other aspects, exhibited different dc I-V curves, in accordance with the theory of correlated single-electron tunneling. Our results imply that a tunneling electron can effectively probe its electrodynamic environment at distances much larger than c${\mathrm{\ensuremath{\tau}}}_{\mathrm{t}}$, where ${\mathrm{\ensuremath{\tau}}}_{\mathrm{t}}$ is the ``traversal'' time of its passage through the energy barrier.