Effects of applied electric fields on the infrared transitions between hydrogenic states in GaAs low-dimensional systems

Abstract

Using a variational procedure within the effective-mass approximation we calculate the binding and transition energies of shallow-donor impurities in cylindrical pills of GaAs low-dimensional systems, under the action of an electric field applied in the axial direction, and considering 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 the presence of the electric field breaks the axial symmetry for the binding energy of the ground and excited states of the impurity and together with the impurity position, the geometric confinement is determinant for the existence of bounded excited states in these structures. In the two-dimensional limit and with low electric fields we obtained the expected four effective Rydbergs for the binding energy of the 1s-like 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. ͓S0163-1829͑97͒02716-1͔

Magnetic field dependence of the binding energy of shallow donors in GaAs quantum-well wires

“…Montes et al [6] have studied the action of an external electric field on the binding energy of the ground and the first few excited states for a shallow impurity in a rectangular GaAs QWW. Duque et al [7] have calculated infrared transitions between hydrogenic states in donor impurities in cylindrical GaAs lowdimensional systems with applied electric field. Magnetic-field experiments are also important for studying low-dimensional systems because of the possibility of varying the size of the wavefunction by varying the field strength.…”

Effects of hydrostatic pressure on the donor binding energy and intra donor transition matrix elements in GaAs–GaAlAs quantum wells

“…This means that in the Hamiltonian in Eq. (1), we take w b ( , ) ( , ) P T P T ε ε = [25]. The pressure dependent potential energy which confines the donor electron in the well layer regions given by:…”

1 s–2 p±transitions between hydrogenic states in GaAs low-dimensional systems under external fields

“…Chiba and Ohnishi [13] have investigated quantum-confined Stark effects on the electronic structure of a GaAs microcluster and have analyzed the electric field-ionization mechanism for a confined exciton. The theoretical results by Montes et al [14] and Duque et al [15] show that the presence of the electric field in cylindrical GaAs low-dimensional systems (LDSs), together with the donor position, is determinant for the existence of bounded excited states in these structures. The optical properties of correlated electrons in quantum dots with small confinement in a strong magnetic field [16] and the effect of free carriers on photoluminescence from modulation-doped self-assembled QDs in a magnetic field [17] have been studied by Wojs et al In this work we study the effects of electric and magnetic fields, both applied parallel to axis of a cylindrical GaAs LDS, on the binding and transition energies between the 1s-like ground state and 2 p ± -like excited states of a donor impurity.…”