Browsing by Author "Brandi, H. S."

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    Laser-dressing and magnetic-field effects on shallow-donor impurity states in semiconductor GaAs–Ga1−xAlxAs cylindrical quantum-well wires
    (2010-01) López, F. E.; Reyes Gómez, E.; Porras Montenegro, Nelson; Brandi, H. S.; Oliveira, L. E.
    The influence of an intense laser field on shallow-donor states in cylindrical GaAs–Ga1−xAlxAs quantum-well wires under an external magnetic field applied along the wire axis is theoretically studied. Numerical calculations are performed in the framework of the effective-mass approximation, and the impurity energies corresponding to the ground state and 2p ± excited states are obtained via a variational procedure. The laser-field effects on the shallow-donor states are considered within the extended dressed-atom approach, which allows one to treat the problem 'impurity + heterostructure + laser field + magnetic field' as a renormalized 'impurity + heterostructure + magnetic field' problem, in which the laser effects are taken into account through a renormalization of both the conduction-band effective mass and fundamental semiconductor gap.
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    Laser-dressing effects on the electron g factor in low-dimensional semiconductor systems under applied magnetic fields
    (2009-05) López, F. E.; Reyes Gómez, E.; Brandi, H. S.; Porras Montenegro, Nelson; Oliveira, L. E.
    The effects of a laser field on the conduction-electron effective Landé g factor in GaAs–Ga1−xAlxAs quantum wells and quantum-well wires under applied magnetic fields are studied within the effective-mass approximation. The interaction between the laser field and the semiconductor heterostructure is taken into account via a renormalization of the semiconductor energy gap and conduction-electron effective mass. Calculations are performed for the conduction-electron Landé factor and g-factor anisotropy by considering the non-parabolicity and anisotropy of the conduction band. Theoretical results are obtained as functions of the laser intensity, detuning and geometrical parameters of the low-dimensional semiconductor heterostructures, and indicate the possibility of manipulating and tuning the conduction-electron g factor in heterostructures by changing the detuning and laser-field intensity.