Charge oscillations in double quantum wells: Nonlinear effects caused by the Coulomb interaction

The influence of the Coulomb interaction on the coherent dynamics of the photoexcited electrons in double quantum wells is studied in the Hartree-Fock approximation. Since the Coulomb energy of the system depends on the position of the oscillating electronic wave packet, a time-dependent renormalization of the levels splitting energy takes place. Time evolution of the electron density distribution is described by the equation for a classical anharmonic oscillator motion. The dependence of the period and the amplitude of the oscillations on the excited electrons concentration is calculated. Dephasing effects due to the Coulomb interaction are discussed.