Extension of Classical Nucleation Theory for Uniformly Sheared Systems

TL;DR

This paper extends classical nucleation theory to account for shear flow effects by incorporating anisotropy and an effective temperature, validated through molecular dynamics simulations showing a maximum nucleation rate at specific shear conditions.

Contribution

It introduces a shear-dependent extension of classical nucleation theory that accounts for anisotropy and effective temperature without altering thermodynamics.

Findings

Nucleation rate peaks when relaxation time matches inverse shear rate.

Shear influences nucleation mainly through kinetic prefactors and effective temperature.

The extended theory aligns well with molecular dynamics simulation results.

Abstract

Nucleation is an out-of-equilibrium process, which can be strongly affected by the presence of external fields. In this letter, we report a simple extension of classical nucleation theory to systems submitted to an homogeneous shear flow. The theory involves accounting for the anisotropy of the critical nucleus formation, and introduces a shear rate dependent effective temperature. This extended theory is used to analyze the results of extensive molecular dynamics simulations, which explore a broad range of shear rates and undercoolings. At fixed temperature, a maximum in the nucleation rate is observed, when the relaxation time of the system is comparable to the inverse shear rate. In contrast to previous studies, our approach does not require a modification of the thermodynamic description, as the effect of shear is mainly embodied into a modification of the kinetic prefactor and of the temperature.