k→⋅p→ theory, effective-mass approach, and spin splitting for two-dimensional electrons in GaAs-GaAlAs heterostructures

A five-level k→⋅p→ theory is developed for conduction-band electrons in heterostructures. A local effective mass and a local g factor are obtained which depend on the variation of the p-type valence- and higher conduction-band edges. The effective mass and the spin splitting found in cyclotron and spin-resonance experiments are explained. A finite spin splitting is obtained at zero magnetic field and the possibility of determining the interface discontinuity from the spin splitting is discussed.