The electronic dynamics of a coupled-quantum-dot structure driven by an AC field

Abstract

We theoretically investigate electronic dynamic behavior in a coupled-quantum-dot structure driven by an AC field. Based on the density-matrix theory, the time evolution of the electron occupation probability is shown by solving a coupled nonlinear equation in combination with Coulomb charging effect. The AC field leads to the changes of the oscillation behavior of the electron, which is investigated in several frequency regions. The field at a certain frequency can induce the transition of suppression and enhancement of the electronic delocalization with various Coulomb charging energy. But in very high-frequency, the field has little effect on the electronic dynamics. In the region of photon-assisted tunneling, the minimal time for the electron tunneling to the other dot decreases with increasing the frequency of the field. In addition, the Coulomb charging energy enhances the dynamical suppression of electronic delocalization. The strong electronic localization is found in the weak coupling quantum dots. The results show that a single-electron switch may be realized in the structure.