Nonlinear stochastic discrete drift-diffusion theory of charge fluctuations and domain relocation times in semiconductor superlattices -: art. no. 195308

A stochastic discrete drift-diffusion model is proposed to account for the effects of shot noise in weakly coupled, highly doped semiconductor superlattices. Their current-voltage characteristics consist of a number of stable branches corresponding to electric field profiles displaying two domains separated by a domain wall. If the initial state corresponds to a voltage on the middle of a stable branch and is suddenly switched to a final voltage corresponding to the next branch, the domains relocate after a certain delay time. Shot noise causes the distribution of delay times to change from a Gaussian to a first passage time distribution as the final voltage approaches that of the end of the first current branch. These results agree qualitatively with experiments by Rogozia [Phys. Rev. B 64, 041308(R) (2001)].