Exchange effects in electron-hole plasma in quantum well heterostructures under an electric field

Numerical calculations are presented for the electron-hole plasma density dependence of the ground-state subband energies and carrier's wave functions in GaAs/AlxGa1-xAs quantum-well heterostructure subjected an electric field. We show that both the Hartree and exchange interactions cause the electron and hole self-energies to highly depend on the plasma density. In contrast, only a weak dependence of the spatial extent of the wave functions, due to exchange interactions, on the plasma density has been found.Our calculations also reveal a strong competition between the exchange and Hartree interactions as a function of plasma density, that in general, depends on the electric field and quantum-well width. The results of numerical calculations of the band-gap renormalization due to many- body effects are used to infer the bistable behavior of the quantum-well heterostructures in an electric field under near band-gap photoexcitation.