Theory of one-dimensional quantum pump based on a two-barrier structure

A 1D quantum pump based on a structure of two δ-functional harmonically oscillating potentials is considered. Such a structure can pump electrons from one bank to the other. An ac perturbation induces a steady-state current. The effect takes place in spatially asymmetric systems. Such an asymmetry is formed due to a difference in the initial heights of the barriers or in the amplitudes or phases of ac signals. The pump can operate in various modes depending on its parameters. It is shown that the current displays oscillations with a period such that the wavelength of incident or excited electrons is multiple to the separation of the δ-functions. Resonances at quasi-stationary states between the barriers, at zero energy, and with stationary states (in the case of wells) are investigated.