Sinusoidal gate voltages for a three-gate single electron pump

The characteristics of a three-gate single electron pump with four small tunnel junctions have been studied by simple calculations. Comparing the charging energy of a three-gate pump for different configurations of excess electrons, we obtained the equilibrium energy planes in a three dimensional (3D) gate-voltage space. The polygon formed by the union of the equilibrium energy planes for all configurations nearest to a given configuration is depicted in the 3D space. Inside the polygon, the configuration of excess electrons is stable. The pump can be operated by applying a set of sinusoidally varying gate voltages, whose trajector in the 3D space is presented