Magnetospectral analysis of tunneling processes in a double-quantum-well tunneling structure

Using high magnetic fields to tune the Landau-level separation through phonon energies, we identify the off-selection-rule tunneling processes in an ${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As/GaAs double-quantum-well tunneling structure. Different elastic and inelastic tunneling mechanisms are identified. The effective mass of the tunneling electrons is directly determined from the crossing point of the elastic and inelastic processes. We observe the field-induced suppression of the elastically scattered contribution to the peak tunneling current. An upper limit on the resonant part of the tunneling current is established.