EXPERIMENTAL AND THEORETICAL-STUDY OF MAGNETODONORS IN GAAS AND INP AT MEGAGAUSS FIELDS

Donor states in GaAs and InP at megagauss magnetic fields are studied experimentally and theoretically. The data allow us to investigate the magnetodonors for values of gamma = ($) over bar h omega(c)/2Ryappro ximate to 10, unattainable until now in these materials. The observati ons are described by a theoretical model, which uses variational atomi c-magnetic wave functions and accounts for the band nonparabolicity wi thin an effective two-band k.p formalism. The theory describes well th e absolute values and field dependences of energy shifts between the c yclotron resonance (CR) transitions and the corresponding magnetodonor impurity cyclotron resonance (ICR) transitions in both materials. Spi n doublets of CR and ICR transitions are considered; they are shown to be related to a variation of the spin g value with the energy. It is argued that the spin-doublet splittings at high fields should be consi derably larger in GaAs than in InP. This conclusion agrees with the ob servations.