Enhancement of 2D → 2D tunneling by Γ-XZ mixing in GaAs/AlAs resonant tunneling structures at high pressure

Abstract

We have investigated the 2D → 2D resonant tunneling in coupled X-band double quantum well structures, which can be achieved in GaAs/AlAs heterostructures by using high hydrostatic pressure. Until recently, there has been clear observation of 2D → 2D resonant tunneling between confined transverse XX,Y states but not between longitudinal XZ states. In this paper, we demonstrate the existence of such resonant tunneling in samples with very thin well and barrier layers. The existence of detectable 2D → 2D resonant tunneling between XZ states, even in a structure with a barrier thickness of 40 Å, is striking. However, by modelling the transport in terms of quantum beats between symmetric and anti-symmetric double well states, we show that Γ-XZ mixing can produce enhancements of up to ≈102