# Bichaoticity Induced by Inherent Birhythmicity during the Oscillatory Electrodissolution of Silicon

## TL;DR

This study reveals that silicon electrodissolution exhibits inherent birhythmicity and bichaoticity, with two distinct routes to chaos, highlighting complex feedback mechanisms in its oscillatory electrochemical behavior.

## Contribution

It demonstrates for the first time that silicon electrodissolution shows inherent birhythmicity and bichaoticity, with different chaos transition routes in a wide parameter range.

## Key findings

- Presence of two distinct feedback loops causing birhythmicity.
- Existence of bistability with multimode oscillations.
- Different routes to chaos: period-doubling and quasiperiodic transition.

## Abstract

The electrodissolution of p-type silicon in a fluoride-containing electrolyte is a prominent electrochemical oscillator with a still unknown oscillation mechanism. In this article, we present a study of its dynamical states occurring in a wide range of the applied voltage - external resistance parameter plane. We provide evidence that the system possesses inherent birhythmicity, and thus at least two distinct feedback loops promoting oscillatory behaviour. The two parameter regions in which the different limit cycles exist are separated by a band in which the dynamics exhibit bistability between two branches with different multimode oscillations. Following the states along one path through this bistable region, one observes that each branch undergoes a different transition to chaos, namely a period-doubling cascade and a quasiperiodic route with a torus-breakdown, respectively, making Si electrodissolution one of the few experimental systems exhibiting bichaoticity.