Collision and capture dynamics in a quantum dot: The role of doubly excited states

We investigate collision dynamics involving two electrons and a quantum dot embedded in a quantum wire. One electron is initially at rest in the ground state of the dot, whereas the other electron is incident on the dot with a rather well defined velocity. Excitation, reflection and transmission probabilities are obtained by resolving the dynamics explicitly. Also, the probability of both electrons being unbound after collision is studied. 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.