Negative Differential Resistance and Super-Poissonian Shot Noise in a System of Single Electron Transistors

Currents and their fluctuations in two capacitively coupled single electron transistors were studied within the sequential tunneling approach. A special attention was focused on the effect of the negative differential resistance, which appears due to the Coulomb interactions of accumulated charges on both the single electron transistors. In this case large polarization fluctuations are activated, which results in a significant enhancement of the current shot noise.