Dynamical control of electronic states in AC-driven quantum dots

Abstract

We investigate the dynamics of two interacting electrons moving in a one‐dimensional array of quantum dots, under the influence of an ac field. The quantum dot array is modeled as a single‐band tight‐binding model of Hubbard‐type, and the system is analyzed by means of the Floquet approach. Our results show that the system exhibits two distinct regimes of behavior, depending on the ratio of the strength of the driving field to the inter‐electron Coulomb repulsion. When the ac‐field dominates an effect termed coherent destruction of tunneling occurs at certain frequencies, in which transport along the array is suppressed. In the other, weak‐driving, regime we find the surprising result that the two electrons can bind together into a single composite particle — despite the strong Coulomb repulsion between them — which can then be controlled by the ac field in an analogous way. We show how calculation of the system’s Floquet quasienergies explains these results, and thus how ac fields can be used to control ...