Chaotic motion of space charge wave fronts in semiconductors under time-independent voltage bias - art. no. 056216

A standard drift-diffusion model of space charge wave propagation in semico nductors has been studied numerically and analytically under de voltage bia s. For sufficiently long samples, appropriate contact resistivity, and appl ied voltage-such that the sample is biased in a regime of negative differen tial resistance-we find chaos in the propagation of nonlinear fronts (charg e monopoles of alternating sign) of electric field. The chaos is always low dimensional, but has a complex spatial structure; this behavior can be int erpreted using a finite-dimensional asymptotic model in which the front (ch arge monopole) positions and the electrical current are the only dynamical variables.