Modeling of an adiabatic tunable-barrier electron pump

We present a model for the operation of a single-island adiabatic electron pump with field-effect transistors acting as tunable barriers. We account for the electrostatics by modeling the capacitive network and fit the parameters of the gate-dependent barrier conductances which include exponential dependence in the subthreshold regime. This procedure results in the knowledge of the parametric dependence of the tunneling rates in the master equation for sequential tunneling. We compute the pumping current by numerically integrating the time-dependent master equation along a closed contour traversed in the gate voltage plane by the two out-of-phase harmonic signals that drive the pump. Basic features expected for a quantized adiabatic pump are reproduced by the calculation which will be extended to explore and differentiate the error mechanisms of the pump.