Wave fronts may move upstream in semiconductor superlattices
In weakly coupled, current biased, doped semiconductor superlattices, domain walls may move upstream against the flow of electrons. For appropriate doping values, a domain wall separating two electric-field domains moves downstream below a first critical current, it remains stationary between this value and a second critical current, and then moves upstream above. These conclusions are reached by using a comparison principle to analyze a discrete drift-diffusion model, and validated by numerical simulations. Possible experimental realizations are suggested.
Carpio
A
Departamento de Matematica Aplicada, Universidad Complutense, Madrid, Spain.
Bonilla
LL
Wacker
A
Scholl
E