Controlling local order of athermal self-propelled particles

TL;DR

This paper investigates how active, self-propelled forces influence local structural order in a model of athermal particles, revealing that non-equilibrium forces promote icosahedral order and enable access to low-energy configurations.

Contribution

It demonstrates that non-equilibrium active forces enhance icosahedral order in a binary mixture, facilitating exploration of low-energy states not easily reachable by passive dynamics.

Findings

Active forces promote icosahedral local order.

Non-equilibrium dynamics access low potential energy states.

Active particles explore the potential energy surface more effectively.

Abstract

We consider a model of self-propelled dynamics for athermal active particles, where the non-equilibrium active forces are modelled by a Ornstein-Uhlenbeck process. In the limit of no-driving force, the model reduces to the passive, Brownian dynamics of an atomistic glass forming fluid, the Wahnstr\"om binary mixture. The Wahnstr\"om mixture is known to show strong correlations between the emergence of slow dynamics and the formation of locally favoured structures based on icosahedra. Here, we study how the non-equilibrium forces affect the local structure of the system, and find that these strongly promote icosahedral order. The phases rich in local icosahedral order correspond to configurations of very low potential energy, suggesting that the non-equilibrium dynamics in the self propelled model can be effectively exploited to explore the potential energy surface of the binary mixture and have access to states that are difficult to attain using passive dynamics.