Double-charge solitons in one-dimensional array of mesoscopic junctions

We show that there exist double-charge solitons in a one-dimensional mesoscopic junction array in which there are two excess electrons respectively on two different islands. The prominent feature of a double-charge soliton is its potential peak splitting into double peaks. The two peak values are not equal generally. The dependences of the peak potentials and threshold voltage of a double-charge soliton on the structure parameters of the tunnel junction array are also discussed. We also propose an equivalent single-charge soliton description for a double-charge soliton.