Negative differential resistance of a Coulomb blockade phenomenon in a junction array of ultrasmall islands

We present a theoretical study of a voltage-biased array of nine ultrasmall islands located close together and positioned in a plane. A main feature of the junction array is that two junctions out of the ten junctions go in the direction opposite to that of an external electric field. Using a semiclassical single electron tunnelling model, we show that the junction array possesses a negative differential resistance (NDR) feature due to single electron charging effects. The array whose islands are 10nm scale would show NDR at tens of kelvins.