Geometrically Induced Multiple Coulomb Blockade Gaps
  We have theoretically investigated the transport properties of a ring-shaped array of small tunnel junctions, which is weakly coupled to the drain electrode. We have found that the long range interaction together with the semi-isolation of the array bring about the formation of stable standing configurations of electrons. The stable configurations break up during each transition from odd to even number of trapped electrons, leading to multiple Coulomb blockade gaps in the the $I-V$ characteristics of the system. 
Mincheol Shin, Seongjae Lee, Kyoung Wan Park, and El-Hang Lee