Devil's staircase, spontaneous-DC bias, and chaos via quasiperiodic plasma oscillations in semiconductor superlattices

TL;DR

This paper investigates plasma instabilities in semiconductor superlattices under AC electric fields, revealing complex behaviors like frequency locking, Devil's staircase structures, and chaos, with implications for understanding nonlinear dynamics in electronic materials.

Contribution

It uncovers the emergence of spontaneous DC bias, frequency locking phenomena, and chaos in plasma oscillations within superlattices, highlighting novel nonlinear effects and their parameter space structures.

Findings

Spontaneous DC bias appears when p or q are even integers.

Frequency locking creates Arnol'd tongues in parameter space.

Transition to chaos occurs via resonance overlap.

Abstract

We study a plasma instability in semiconductor superlattices irradiated by a monochromatic, pure AC electric field. The instability leads to sustained oscillations at a frequency \omega 2 that is either incommensurate to the drive, or frequency-locked to it, \omega 2 = (p/q) \omega. A spontaneously generated DC bias is found when either p or q in the locking ratio are even integers. Frequency locked regions form Arnol'd tongues in parameter space and the ratio \omega 2 / \omega\ exhibits a Devil's staircase. A transition to chaotic motion is observed as resonances overlap.