MANY-BODY EFFECTS IN THE QUASI-ONE-DIMENSIONAL MAGNETOPLASMA

We compare measured and calculated luminescence spectra of quantum wir es in normal magnetic fields. The experiments have been performed on m odulated barrier In0.13Ga0.87As/GaAs quantum wires in magnetic fields up to B = 10.5 T. In the regime of high magnetic fields in which the c yclotron energy omega(c) exceeds the lateral intersubband energy Omega the carriers show the behavior of a fully quantized system. The exper imental magnetoluminescence spectra for different excitation intensiti es are in excellent agreement with calculated spectra. The calculation s contain not only the influence of the strong magnetic held, but also the many-body effects on a Hartree-Fock level in terms of state filli ng, band-gap renormalization, and excitonic correlations with up to fo ur lateral subbands. A magnetic-field-dependent momentum cutoff is int roduced, which ensures that electrons and holes are not pushed out of the quantum win under the influence of the Lorentz force. By fitting t he calculated to the measured spectra we determine the density and the temperature in the one-dimensional magnetoplasma. In contrast to the field-free case (B = 0) the renormalization of one subband is mainly d etermined by the occupation of the other subbands in the high-field re gime because the excitons on one subband form, to a good approximation . an ideal gas. Its formation becomes possible because the symmetry un der continuous rotations in the electron and hole isospin space that i s broken by the lateral confinement is to a good approximation restore d by high magnetic fields, which suppress the motion of the free carri ers along the wire.