Charge transport through quantum dots via time-varying tunnel couplings

Abstract

We describe a novel mechanism for charge pumping through tunnel-coupled quantum dots in the regime of strong Coulomb blockade. The quantum state of an additional electron within the structure is steered by changing the tunneling couplings between neighbouring dots. Appropriate tailoring of the interdot tunneling rates allows to design the instantaneous eigenvalues of the system Hamiltonian. A combination of adiabatic following and Landau-Zener tunneling results in the transfer of charge from one dot to the neighbouring one. Coupling to electron reservoirs via weak tunnel-barriers then allows to implement an electron pump.