EFFECTS OF APPLIED ELECTRIC-FIELDS ON THE INFRARED TRANSITIONS BETWEEN HYDROGENIC STATES IN GAAS LOW-DIMENSIONAL SYSTEMS

Using a variational procedure within the effective-mass approximation we calculate the binding and transition energies of shallow-donor impu rities in cylindrical pills of GaAs low-dimensional systems, under the action of an electric field applied in the axial direction, and consi dering an infinite confinement potential. We calculate the binding and transition energies as a function of the system geometry, the applied electric field, and the donor-impurity position. We have found that t he presence of the electric field breaks the axial symmetry for the bi nding energy of the ground and excited states of the impurity and toge ther with the impurity position, the geometric confinement is determin ant for the existence of bounded excited states in these structures. I n the two-dimensional limit and with low electric fields we obtained t he expected four effective Rydbergs for the binding energy of the Is-l ike state. In addition, and only for high electric fields, we obtained the reverse transitions 2p(z)-like-->3s-like and 3p(z)-like-->2s-like .