# FCC-to-BCC phase transitions in convex and concave hard particle systems

## TL;DR

This study uses computer simulations to analyze FCC-to-BCC phase transitions in convex and concave polyhedral and dimpled spherical particles, revealing the first-order nature of these transitions and the influence of particle shape on phase behavior.

## Contribution

It provides new insights into how convexity and concavity of particle shapes affect FCC-to-BCC phase transition pathways in hard particle systems.

## Key findings

- FCC-to-BCC transitions are first order in both convex and concave particle families.
- Shape symmetry influences phase transition pathways.
- Convexity or concavity impacts the free energy landscape of phase transitions.

## Abstract

Particle shape plays an important role in the phase behavior of colloidal self-assembly. Recent progress in particle synthesis has made particles of polyhedral shapes and dimpled spherical shapes available. Here using computer simulations of hard particle models, we study face-centered cubic to body-centered cubic (FCC-to-BCC) phase transitions in a convex 432 polyhedral shape family and a concave dimpled sphere family. Particles in both families have four-, three-, and two-fold rotational symmetries. Via free energy calculations we find the FCC-to-BCC transitions in both families are first order. As a previous work reports the FCC-to-BCC phase transition is first order in a convex 332 family of hard polyhedra, our work provides additional insight into the FCC-to-BCC transition and how the convexity or concavity of particle shape affects phase transition pathways.