Many-body effects in the quasi-one-dimensional magnetoplasma

We compare measured and calculated luminescence spectra of quantum wires in normal magnetic fields. The experiments have been performed on modulated barrier ${\mathrm{In}}_{0.13}$ ${\mathrm{Ga}}_{0.87}$As/GaAs quantum wires in magnetic fields up to B=10.5 T. In the regime of high magnetic fields in which the cyclotron energy ${\mathrm{\omega }}_{\mathrm{c}}$ exceeds the lateral intersubband energy Ω the carriers show the behavior of a fully quantized system. The experimental magnetoluminescence spectra for different excitation intensities are in excellent agreement with calculated spectra. The calculations contain not only the influence of the strong magnetic field, but also the many-body effects on a Hartree-Fock level in terms of state filling, band-gap renormalization, and excitonic correlations with up to four lateral subbands. A magnetic-field-dependent momentum cutoff is introduced, which ensures that electrons and holes are not pushed out of the quantum wire under the influence of the Lorentz force. By fitting the 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 determined by the occupation of the other subbands in the high-field regime because the excitons on one subband form, to a good approximation, an ideal gas. Its formation becomes possible because the symmetry under continuous rotations in the electron and hole isospin space that is broken by the lateral confinement is to a good approximation restored by high magnetic fields, which suppress the motion of the free carriers along the wire.