Self-assembly of three-dimensional ensembles of magnetic particles with laterally shifted dipoles

TL;DR

This study investigates how lateral shifts of dipole moments in spherical colloidal particles influence their ground state configurations and self-assembly behavior, revealing significant effects on structure formation.

Contribution

It introduces a model of shifted dipoles in spherical particles and analyzes their ground states and self-assembly, highlighting the impact of dipole shift on structure formation.

Findings

Shift of dipole affects ground state configurations.

Dipole shift influences self-assembled structures.

Results show crucial impact of dipole position on assembly.

Abstract

We consider a model of colloidal spherical particles carrying a permanent dipole moment which is laterally shifted out of the particles' geometrical centres, i.e. the dipole vector is oriented perpendicular to the radius vector of the particles. Varying the shift $\delta$ from the centre, we analyze ground state structures for two, three and four hard spheres, using a simulated annealing procedure. We also compare to earlier ground state results. We then consider a bulk system at finite temperatures and different densities. Using Molecular Dynamics simulations, we examine the equilibrium self-assembly properties for several shifts. Our results show that the shift of the dipole moment has a crucial impact on both, the ground state configurations as well as the self-assembled structures at finite temperatures.