Binding Energy of the Electron–Hole Liquid in Type-II (GaAs)_m/(AlAs)_m Quantum Wells

Abstract

The binding energy of quasi-two-dimensional electron–hole liquid (EHL) at zero temperature is calculated for type-II (GaAs)_m/(AlAs)_m (5≤m≤13) quantum wells (QWs). The correlation energy is evaluated by adopting a random phase approximation of Hubbard. For comparison, we calculate the binding energy of EHL for type-I (GaAs)_m/(AlAs)_m (14≤m≤20) QWs. It is demonstrated that the EHL in type-II GaAs/AlAs QWs is more stable state than exciton and biexciton at high excitation density, while the EHL is unstable in type-I GaAs/AlAs QWs.