Scattering in a quantum dot: the role of resonances

The dynamics of a system in which an electron is incident on a populated quantum dot is studied by resolving the time dependence of the system. Specifically, one electron is initially at rest in the ground state of the dot, whereas the incident electron has a narrow velocity distribution. In addition to the probabilities of reflection and transmission, the probability of excitation is found as a function of energy. Moreover, probabilities of both electrons being ejected or both being captured are obtained. The latter process involves spontaneous emission. It is found that the dynamics is strongly influenced by the presence of doubly excited states; reflection becomes considerably more probable in the energetic vicinity of such states. This, in turn, contributes to an increase in the probability of trapping also the second electron within the dot