The excitation spectra and superfluidity of the electron-hole system in coupled quantum wells

Excitation spectra and superfluidity of the electron-hole (e-h) system in coupled quantum wells are considered. Rearrangement of the ground state due to strong e-h pairing and e-e interactions is performed in the middle and strong coupling regimes by account of correlation effects depending on Bogolubov u, v coefficients and by subsequent minimization of the total energy of the system on u, v parameters. The dependence of the spectra on interwell distance and density of electrons and holes in coupled quantum wells is analyzed. The temperature of appearance of the superfluidity in the system (Kosterlitz-Thouless transition temperature) has been estimated at different interwell separations D.