Pressure induced transition of direct to indirect excitons in double quantum well: Effect of Γ-X crossover

Abstract

Influence of Γ-X crossover due to applied hydrostatic pressure on exciton dynamics has been studied in symmetric GaAs/Al 0.3 Ga 0.7 As double quantum wells using variation technique and effective mass approximation. The effect of Γ-X crossover is significant in narrow wells irrespective of the coupling, type of excitons and nature of confinement. The stability of both direct and indirect excitons has been analysed from spatial extension and diamagnetic susceptibility. At P > P 2 Kbar, change of confinement of electron from Γ to X band state would form a spatially indirect exciton with reduced spatial extension. This study confirms that the complete transition of direct to indirect exciton can be achieved through the application of pressure. The change in inter-band transition energy due to Γ-X crossover may lead to a shift in Photoluminescence peak energy. • Effect of Γ-X crossover is significant in narrow wells irrespective of the coupling. • The change is also dependant on the type of exciton. • At P > P 2 Kbar, change of confinement of electron from Γ to X band form a spatially indirect exciton. • Transition of direct to indirect exciton can be achieved through the application of pressure. • Change in inter-band transition energy may lead to a shift in Photoluminescence peak.