Lateral current density fronts in globally coupled bistable semiconductorswith S- or Z-shaped current voltage characteristics

We study the propagation of a lateral current density front in a bistable s emiconductor system with S- or Z-shaped current-voltage characteristics. It is demonstrated that an external load circuit introduces a global coupling which leads to positive or negative feedback upon the front dynamics in S- or Z-type systems, respectively. This results in accelerated or decelerate d front motion. The type of feedback can be reversed if the system is opera ted in an active external circuit with negative load resistance. Double bar rier resonant tunneling diodes (DBRT) and heterostructure hot electron diod es (HHED) are used as examples of Z- and S-type systems, respectively.