Single-electron soliton avalanches in tunnel-junction arrays

Numerical modeling of correlated single-electron tunneling in uniform two-dimensional arrays of small conducting islands separated by tunnel junctions shows the possibility of soliton-antisoliton avalanches. Though the time duration of any avalanche and the total charge, ΔQ=ne, transferred across the array during the avalanche are always finite in arrays with length N larger than certain critical value Nc and large width M, the avalanche magnitude n may be exponentially large, resulting in particular in a giant increase of shot noise. Thermal fluctuations gradually suppress the avalanche effect. Background charge disorder may lead (in larger arrays) to a gradual change of avalanche character and to a crossover from the avalanche-induced shot noise to $1/f$-type noise.