The influence of screening function on exciton mott transition in an asymmetric double quantum well

Abstract

The semiconductor-to-metal transition (SMT) due to excitons exciton mott transition (EMT) in GaAs/Al[Formula: see text]Ga[Formula: see text]As asymmetric double quantum well (ADQW) has been studied theoretically by tuning direct (DX) and indirect (IDX) exciton densities using variation technique combined with the Monte Carlo approximation. The interaction of the optically pumped exciton densities is accounted for through the Thomas–Fermi (TF) dielectric screening and compared with Hartree–Fock (HF) screening. The screening effects of IDX at the barrier regime have been accounted for through size-dependent screening. The important characteristics of EMT, such as (i). binding energy and (ii), diamagnetic susceptibility have been studied in both coupled ([Formula: see text]Å) and isolated ([Formula: see text]Å) regimes of ADQW. The effect of asymmetry on the EMT of DX (IDX) is significant only for [Formula: see text] in the case of the coupled regime of ADQW, which may be due to the dynamic tunneling mechanism. The impact of the screening among the exciton densities to bring out the avalanche breakdown of excitons at the critical concentration has been studied for different kinds of excitons.