Full Counting Statistics of Quantized Charge Pumping
We investigate the fluctuations of the electrical current produced by single-electron charge pumps. To this end, we develop a Floquet theory that allows us to evaluate the full counting statistics of transferred charges over a wide range of driving frequencies. For charge pumps controlled by either one or two gate voltages, we demonstrate that our theoretical framework is useful for practical device optimization. Specifically, by optimizing the driving parameters, we predict a significant increase in the frequencies for which a quantized current can be produced. For adiabatic two-parameter pumps, not only the pumped charge but also the noise can be expressed as a surface integral over a Berry curvature in the parameter space. Our findings are important for the efforts to realize high-frequency single-electron pumping, and our predictions may be verified using current technology.