Resonant tunneling via X-point states in AlAs-GaAs-AlAs heterostructures

We have observed resonant tunneling of electrons in AlAs-GaAs-AlAs heterostructures, via a quantum state localized in AlAs. The resonance manifests itself as a distinct feature in the current-voltage characteristics, at 4 K. The confined energy state arises from a potential profile derived from the X point of the Brillouin zone, in which AlAs behaves as a quantum well and GaAs as a barrier.