Emergent Complexity in a Light-Driven Self-Oscillatory Crystal: A Molecular Perspective on Autonomous Behavior and Stimulus-Modulated Motion

TL;DR

This study investigates a light-driven self-oscillatory crystal exhibiting autonomous flipping motion, combining experimental evaluation and modeling to understand the molecular mechanisms and conditions leading to complex, stimulus-dependent behaviors.

Contribution

The paper introduces a validated mechanism and mathematical model explaining how molecular-level processes produce diverse, stimulus-modulated oscillatory behaviors in a self-oscillatory crystal.

Findings

Oscillation frequency depends on light polarization.

Small condition differences lead to diverse behaviors.

Memory effects influence oscillatory motion.

Abstract

Living organisms are molecular systems with self-sustained dynamics via energy conversion through molecular cooperation, resulting in highly complex macroscopic behaviors. Construction of such autonomous macroscopic dynamics at a molecular system level remains one of the central challenges in the field of chemistry. Looking further ahead, constructing motile systems that can receive external information and adapt their autonomous behavior represents the next frontier towards newly functional molecular devices such as microrobots. In this study, we focused on a light-driven self-oscillatory crystal that exhibits continuous flipping motion under constant light irradiation. We experimentally evaluated the oscillation frequency of the crystal under polarized light and confirmed the validity of our previously proposed mechanism, and clarified the requirements for self-oscillation. Based on this mechanism, we constructed a mathematical model that demonstrates the motion of the crystal itself. The model revealed that diverse oscillatory behaviors at the macroscopic level can emerge due to small differences in conditions even when the underlying molecular-level processes are identical. Furthermore, we found that the oscillatory behavior depended on the state generated by the previously applied light. This suggests that a memory effect contributes to the complex motion of the crystal.