Relaxation of electron energy in the coupled polar semiconductor quantum dots

The zero-dimensional semiconductor nanostructures belong to the candidates for the realization of the quantum bits. They are expected to be scalable f or the purpose of the tuning their physical properties. In these structures the quantum bit could be realized in the form of a single quantum dot with two electronic energy levels, with only one electron in the dot. As the ba sic states of the quantum bit, realized in this way, the two orbital states of the electron in the dot could be used. It appears however that usually the relaxation of the energy of the electron from the excited energy level is often rather fast in the polar semiconductor quantum dots. It is the pur pose of this paper to present calculations of the relaxation rate of the el ectron in an asymetric pair of tunneling coupled quantum dots, in which the two electronic orbitals of the quantum bit are located each in a separate dot. The calculation of the electronic energy relaxation is based on the mu ltiple electron-LO-phonon scattering processes, implemented to the theory v ia the electronic self-energy taken in the self-consistent Born approximati on. The dependence of the relaxation rate on the geometry of the pair of th e coupled dots and on the lattice temperature is presented for a realistic model of this nanostructure.