Pergamon Solid State Communications, Vol. 98, NO. 3, pp. 215-219, 1996 Copyright 0 1996 Elsevier Science Ltd SOOX?-HW8(96)00037-3 Printed in Great Britain. All rights reserved 0038-1098/96 $12.00 +_OO MAGNETIC FIELD EFFECTS ON DONOR TRANSITIONS IN QUANTUM WELLS L. H. M. Barbosa, A. Latge Instituto de Fisica, Universidade Federal Fluminense, Caixa Postal 100.093,24001-970, Niteroi, Rio de Janeiro, Brazil M. de Dios Leyva*, and L. E. Oliveira Instituto de Fisica, Universidade Estadual de Campinas, Caixa Postal 6165, Campinas, S&I Paula, 13083-970, Brazil zyxwvutsrqpo (Received 28 August 1995; accepted in revised form 16 January 1996 by C. E. T. Goqalves da Silva) The effects of an applied magnetic field on the electronic and far-infrared properties of impurity states in donor-doped GaAs-Ga,_xA$As quantum wells are studied within a variational scheme in the effective-mass approximation, with the magnetic field applied perpendicular to the quantum-well mnterfaces. Theoretical calculations for the Is-like hydrogenic ground state, and first excited 2p*-like states are presented for different values of the magnetic field, and as functions of the quantum-well thickness and position of the donor within the well. The absorption spectra related to Is-2p* intradonor transitions for x-polarised radiation are calculated and results are in quite good agreement with previously reported magneto-spectrosscopic data. Keywords: A. quantum wells, C. impurities in semiconductors Impurity-related properties of intentionally and non- intentionally doped low-dimensional semiconductor systems have been extensively studied in the last years, In particular, the effects of an applied magnetic field on the electronic and far-infrared properties of quantum wells (QW’s) and multiple quantum wells (MQW’s) have been a subject of interest zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 1-7 , since the magnetic field introducer, an additional degree of confinement besides the one imposed by the barrier potential; depending upon the direction of the applied magnetic field, interesting changes in impurity- related far-infrared and electronic properties may be achieved. Magnetospectroscopic measurement!i4-7 associated essentially to intradonor transitions in selectively- *Permanent address: Departamento de Fisica Teorica, Univ. de la Habana, Vedado 10400, La Habana, Cuba. donor-doped Ga4s-Gao7Ak~3As QWs have been reported. Recently, Latge et al8 have enphasized that a proper calculation of the far-infrared absorption spectra should involve a proper consideration of the doping protile, in order to obtain an adequate quantitative understanding of the experimental measurements. In this work we present a theoretical study of the effects of a magnetic field applied perpendicular to the interfaces of a donor-doped GaAs-Gao7Alo,3As QW of well width L, on the energies of the ground- and first- excited states, and on the absorption coefficient related to intradonor transitions. We follow a standard variational scheme within the effective-mass approximation and choose a trial envelope hydrogenic wave function appropriate for 215