Time-correlated single-electron tunneling in one-dimensional arrays of ultrasmall tunnel junctions

Abstract

We have obtained convincing experimental evidence of the time correlation of single-electron tunneling (SET) events, i.e., of SET oscillations with the average frequency ${f}_{s}$ fundamentally related as ${f}_{s}$=I/e to the dc current I. The experiments have been carried out with one-dimensional N-junction arrays of Al/oxide/Al tunnel junctions of area S\ensuremath{\approxeq}0.006 \ensuremath{\mu}${\mathrm{m}}^{2}$ at T\ensuremath{\approxeq}60 mK. The correlation showed up as resonance peaks of the dynamic resistance dV/dI as a function of I, arising at I=${I}_{n}$=nef (n=\ifmmode\pm\else\textpm\fi{}1 and \ifmmode\pm\else\textpm\fi{}2) at irradiation of the N=15 and 19 samples by microwaves of frequency f=0.7--5 GHz.