Capacitively coupled 1D-arrays of small tunnel junctions

We have fabricated two nominally identical one-dimensional arrays of small tunnel junctions, each with 10 junctions in series. Each electrode of one array is capacitively coupled to two electrodes in the other array. By measuring the current voltage characteristics of the two arrays simultaneously, we observe a coupling between the currents in the two arrays. In a narrow region of biasing conditions, we find that the currents are equally large but with opposite signs. We interprete this as correlated transport of electrons in one array, and holes in the other array. The experimental results show qualitative agreement with numerical simulations.