Resonant interband tunneling via Landau levels in polytype heterostructures

The low-temperature (T=1.4 K) tunneling current of GaSb-AlSb-InAs-AlSb-GaSb heterostructures has shown sharp negative-differential-resistance features induced by a magnetic field parallel to the current. In addition, the zero-voltage tunneling conductance vanished at certain fields, in close analogy with the behavior of the in-plane conductance in the quantum-Hall-effect regime. These results, which strongly differ from similar experiments in GaAs-${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Al}}_{\mathit{x}}$As resonant-tunneling diodes, are explained in terms of resonant interband tunneling of GaSb holes through Landau levels in the conduction band of the InAs quantum well.