Charged Many-Electron -- Single Hole Complexes in a Double Quantum Well   near a Metal Plate
  It has been shown that the presence of a metal plate near a double quantum well with spatially separated electron and hole layers may lead to a drastic reconstruction of the system state with the formation of stable charged complexes of several electrons bound to a spatially separated hole. Complexes of both the Fermi and the Bose statistics may coexist in the ground state and their relative densities may be changed with the change of the electron and hole densities. The stability of the charged complexes may be increased by an external magnetic field perpendicular to the layers plane. 
V.I. Yudson (Uni. Ulm, Germany; Inst. of Spectroscopy, Russia)