Chaotic dynamics of electric-field domains in periodically driven superlattices

TL;DR

This paper investigates the complex chaotic behavior of electric-field domains in superlattices under periodic driving, revealing various nonlinear dynamical regimes, entrainment phenomena, and coexistence of multiple domains through numerical simulations.

Contribution

It introduces a detailed analysis of how external microwave signals influence electric-field domain dynamics, highlighting the emergence of chaos and domain coexistence in superlattices.

Findings

Identification of chaotic regimes at the boundaries of entrainment regions.

Demonstration of coexistence of multiple electric-field domains.

Observation of Arnol'd tongues indicating entrainment phenomena.

Abstract

Self-sustained time-dependent current oscillations under dc voltage bias have been observed in recent experiments on n-doped semiconductor superlattices with sequential resonant tunneling. The current oscillations are caused by the motion and recycling of the domain wall separating low- and high-electric- field regions of the superlattice, as the analysis of a discrete drift model shows and experimental evidence supports. Numerical simulation shows that different nonlinear dynamical regimes of the domain wall appear when an external microwave signal is superimposed on the dc bias and its driving frequency and driving amplitude vary. On the frequency - amplitude parameter plane, there are regions of entrainment and quasiperiodicity forming Arnol'd tongues. Chaos is demonstrated to appear at the boundaries of the tongues and in the regions where they overlap. Coexistence of up to four electric-field domains randomly nucleated in space is detected under ac+dc driving.