BINDING-ENERGIES AND PHOTOIONIZATION TRANSITIONS OF 2-DIMENSIONAL NEGATIVE DONOR CENTERS D- IN HIGH MAGNETIC-FIELDS

The binding energies of two-dimensional (2D) negative donor centers D- with two electrons bound to the donor ion in the singlet and triplet states in a strong magnetic field are obtained. It is shown that the energies of photoionization transitions D- --> N, in which one electron is excited from zero to the Nth Landau level exceed considerably the binding energies of D-. The absorption by the triplet ground state is shown to differ from that of the singlet by an additional line which occurs at energies lower than the cyclotron energy HBAR-omega(c) and the corresponding dipole-allowed transition does not lead to the photoionization of D-.