Voltage bistability is demonstrated at low temperature in a biased unipolar GaAs/AlGaAs superlattice, using a design based on tunneling from a charge reservoir into a Wannier-Stark ladder and competition between nearest and next-nearest neighbor coherent injection channels. The static conduction characteristics are accounted for by a density matrix approach of coherent injection in an inhomogeneous three-level system with resistive load. Electrostatic retroaction on the energy levels is shown to provide an adequate nonlinear feedback mechanism for bistability, as well as for other instability regimes including sustained Bloch oscillation above a retroaction threshold.

• Received 11 July 2014
• Revised 26 May 2015

DOI:https://doi.org/10.1103/PhysRevB.91.245308