Electron tunneling through indirect single barriers

Electron tunneling through single barriers, taking into account the coupling between two different band-edge profiles, is studied by means of a heuristic two-band tight-binding model. The tunneling probabilities, as well as the spectral weights of the tunneling states, are analyzed. This indirect-barrier system directly addresses the issue of Γ-X coupling in GaAs-(Al,Ga)As heterostructures. A relation between this physical system and the resonant tunneling through double-barrier quantum wells and also the atomic-potential scattering is established. The nature of the resonances in the transmission probabilities is discussed and it is shown under which conditions the shape of these resonances can change.