The boundary between electric-field domains in semiconductor superlattices represents a tunneling barrier. While most of the superlattice is coupled resonantly the current through the superlattice is limited by nonresonant tunneling at the domain boundary. The emitter and collector are purely two dimensional and the system therefore acts as a model system for tunneling between 2D systems. For magnetic fields applied parallel to the layers the average current through the single barrier increases, in contrast to 3D and quasi-2D emitters.

• Received 14 June 1991

DOI:https://doi.org/10.1103/PhysRevLett.67.1618