DOUBLE QUANTUM-WELL ELECTRON-HOLE SYSTEMS IN STRONG MAGNETIC-FIELDS

Two-dimensional electron-hole systems with long excitonic life-times can be realized in double quantum well systems by applying an electric field which localizes electrons and holes in opposite wells. The ground state of such a system is investigated theoretically and numerically in the strong magnetic field limit. It is shown that when the separation between the electron layer and the hole layer, d, is small, an excitonic condensate state is realized. On the other hand, when d is large, either independent fractional quantum Hall states for electrons and holes or coupled Wigner crystal (dipole density wave) states may be realized depending on the filling factor. The difference in photoluminescence spectra between these states is discussed.