Entropic Stabilization of Tunable Planar Modulated Superstructures

TL;DR

This paper demonstrates how a simple isotropic interaction model can produce tunable, thermodynamically stable hexagonal superstructures with nanoparticle assemblies, controllable via temperature changes.

Contribution

It introduces a two-dimensional simulation model showing reversible tuning of superstructure lattice vectors through temperature, supported by free energy calculations.

Findings

Particles form hexagonal superstructures with tunable lattice vectors

Superstructures are thermodynamically stable confirmed by free energy calculations

Temperature controls the reversible structural modulation

Abstract

Self-assembling novel ordered structures with nanoparticles has recently received much attention. Here we use computer simulations to study a two-dimensional model system characterized by a simple isotropic interaction that could be realized with building blocks on the nanoscale. We find that the particles arrange themselves into hexagonal superstructures of twin boundaries whose superlattice vector can be tuned reversibly by changing the temperature. Thermodynamic stability is confirmed by calculating the free energy with a combination of thermodynamic integration and the Frenkel-Ladd method. Different contributions to the free energy difference are discussed.