Out-of-equilibrium Polymorph Selection in Nanoparticle Freezing
arXiv:2009.05316 · doi:10.1021/acs.jpclett.0c02129
Abstract
The ability to design synthesis processes that are out of equilibrium has opened the possibility of creating nanomaterials with remarkable physico-chemical properties, choosing from a much richer palette of possible atomic architectures compared to equilibrium processes in extended systems. In this work, we employ atomistic simulations to demonstrate how to control polymorph selection via cooling rate during nanoparticle freezing in the case of NiAl, a material with a rich structural landscape. State-of-the-art free-energy calculations allow to rationalize the complex nucleation process, discovering a switch between two kinetic pathways, yielding the equilibrium structure at room temperature and an alternative metastable one at higher temperature. Our findings address the key challenge in the synthesis of nano-alloys for technological applications, i.e., rationally exploiting the competition between kinetics and thermodynamics by designing a treatment history that forces the system into desirable metastable states.
References in corpus (15)
- Escaping free-energy minima
- PLUMED 2: New feathers for an old bird
- Melting, freezing, and coalescence of gold nanoclusters
- Formation of an Icosahedral Structure during the Freezing of Gold Nanoclusters: Surface-Induced Mechanism
- Entropy based fingerprint for local crystalline order
- Predicting polymorphism in molecular crystals using orientational entropy
- Enhancing entropy and enthalpy fluctuations to drive crystallization in atomistic simulations
- Navigating at Will on the Water Phase Diagram
- Atomistic Mechanisms for the Nucleation of Aluminium Oxide Nanoparticles
- Finding Efficient Collective Variables: The Case of Crystallization
- Can Ordered Precursors Promote the Nucleation of Solid Solutions?
- Alloy, Janus and core-shell nanoparticles: Numerical modeling of their nucleation and growth in physical synthesis
- Comparison of aluminum oxide empirical potentials from cluster to nanoparticle
- Classical nucleation theory predicts the shape of the nucleus in homogeneous solidification
- Lattice induced crystallization of nanodroplets: the role of finite-size effects and substrate properties in controlling polymorphism