Control of coherence resonance in semiconductor superlattices

TL;DR

This paper investigates how time-delayed feedback control influences noise-induced charge dynamics in semiconductor superlattices, demonstrating the ability to enhance or suppress coherence resonance and revealing delay-induced bifurcations.

Contribution

It introduces a method to control coherence resonance in semiconductor superlattices using time-delayed feedback, including analysis of delay-induced bifurcations.

Findings

Delayed feedback can enhance coherence resonance.

Proper parameter selection can suppress stochastic charge motion.

Delay-induced homoclinic bifurcation is identified.

Abstract

We study the effect of time-delayed feedback control and Gaussian white noise on the spatio-temporal charge dynamics in a semiconductor superlattice. The system is prepared in a regime where the deterministic dynamics is close to a global bifurcation, namely a saddle-node bifurcation on a limit cycle ({\it SNIPER}). In the absence of control, noise can induce electron charge front motion through the entire device, and coherence resonance is observed. We show that with appropriate selection of the time-delayed feedback parameters the effect of coherence resonance can either be enhanced or destroyed, and the coherence of stochastic domain motion at low noise intensity is dramatically increased. Additionally, the purely delay-induced dynamics in the system is investigated, and a homoclinic bifurcation of a limit cycle is found.