THE MAGNETIC-FIELD DEPENDENCE OF SHALLOW DONOR IMPURITY STATES IN GAAS GAALAS MULTIQUANTUM WELLS - A NONVARIATIONAL APPROACH/

We present a novel approach to the calculation of shallow impurity sta tes in single-and multi-quantum-well systems. The Schrodinger equation is directly integrated numerically using an iterative technique. Thus , by avoiding a variational ansatz for the wave function and including a proper treatment of the coupling between the wells, the whole range from low to high magnetic fields as well as from the two-dimensional to the three-dimensional limit is treated on the same level. For the c ase of a single quantum well we discuss the dependence of the binding energies on the magnetic field as well as on the position of the impur ity. For the case of a multi-quantum-well system we analyse the influe nce of the barrier width on the energies and the localization of the w ave functions and we show that for barriers thicker than about 10 nm a single-well analysis is sufficient. A comparison with experimental re sults shows good agreement.