MAGNETOOPTICAL ABSORPTION-SPECTRUM OF A D- ION IN A GAAS-GA0.75AL0.25AS QUANTUM-WELL

The magneto-optical absorption spectrum of a D- ion in a GaAs-Ga0.75Al0.25As quantum well is calculated. We used the variational method based on a two-orbital picture of a D- ion, in which each wave function is represented by a linear combination of anisotropic Gaussian orbitals. The calculated magnetic-field dependence of the binding energy of a D- ion agrees qualitatively with the experimental result. In a magnetic field perpendicular to the well interface, the energies of the one-electron excited states of a D- ion are completely quantized, and broadening is essential for the calculation of the line shape of the magneto-optical absorption spectrum. We considered two types of broadening effect, lifetime broadening and inhomogeneous broadening. Only the lifetime broadening effect reproduces fairly well the observed line shape of the magneto-photoconductivity spectrum. The assumed value of the lifetime is consistent with the measured Hall mobility. © 1995 The American Physical Society.