The Electron Dynamics Of Quantum Dot Arrays With Pumping

Due to variety of reasons, quantum dots array will inevitably exist various impurities. So it is necessary to study the influence of impurity on quantum dots array. In this thesis, we will use one-dimensional tight-binding model to investigate the influence of time-dependent impurity (pumping) on quantum dots array. In this paper, the work is arranged as follows:In Chapter 1, we briefly introduce Basic knowledge of quantum dots array ,i.e., an electrochemical assembly technology for quasi-periodic quantum dots array, transport properties of one-dimensional quantum dots array with electric field and Local density of states of dc-biased superlattices.In Chapter 2, the influence of time-dependent impurity on the electronic and transport properties of the tilted quantum dots array modeled by the tight-binding Hamiltonian is investigated. The quasienergies of the system are calculated in two methods: exact diagonalization and Floquet replica technique .the subtle effects of the impurity on the dynamics of the system are discussed in detail. Through a perturbative analysis in terms of the inverse of the time-dependent impurity frequency, we obtain the time-independent effective Hamiltonian, whose reliability and physical implication are discussed.In Chapter 3, the coherent dynamics of dc-driven quantum dots array with two embedded time-dependent impurities has been investigated, the exact crossings and avoided crossings in the quasienergies are associated with the evolution dynamics of the electron by the introduction of the envelope lines of the site's maximum returning probability. Through a perturbative scheme, the time-dependent Hamiltonian is replaced by an equivalent static one, whose structure discloses the novel quantum tunneling mechanism in the time-periodic driving system. Chapter 4 gives a summary of this thesis.