Binding and transition energies of shallow impurities in cylindrical GaAs quantum-well wires under a uniform magnetic field

We report a calculation of the binding and transition energies of the groun d and some excited states of a hydrogenic donor impurity located at the axi s of a cylindrical GaAs quantum-well wire, under the action of a magnetic f ield applied in the axial direction. Calculations are made using the effect ive-mass approximation within the variational approach for infinite confine ment potential. Our results are obtained for several wire radii and as a fu nction of the applied magnetic field. We have found that some excited state s are not bounded for some values of the radius of the wire and of the appl ied magnetic field. We show how the geometric confinement and the applied m agnetic field split the degeneracy of some excited states. Also, we compare our results with those found in GaAs-(Ga, Al)As quantum wells.