Binding energy of a donor impurity in GaAs image systems under electric and magnetic fields, and hydrostatic pressure

The problem of the impurity binding energy in GaAs n-type delta-doped systems is studied taking the field effect transistor as an archetypical structure. The theoretical investigation considers the effects of externally applied electric and magnetic fields as well as of hydrostatic pressure. The description of the one-dimensional potential profile is made including Hartree and exchange effects via a Thomas–Fermi-based local density approximation. The allowed energy levels are calculated within the effective mass and envelope function approximations by means of an expansion over an orthogonal set of infinite well eigenfunctions. The results for the impurity binding energy are presented also for different configurations of the impurity position within the system.