Fabrication of colloidal Laves phases via hard tetramers and hard spheres: bulk phase diagram and sedimentation behaviour

Abstract

Colloidal photonic crystals display peculiar optical properties which make them particularly suitable for application in different fields. However, the low packing fraction of the targeted structures usually poses a real challenge in the fabrication stage. Here, we propose a novel route to colloidal photonic crystals via a binary mixture of hard tetramers and hard spheres. By combining theory and computer simulations, we calculate the phase diagram as well as the stacking diagram of the mixture, and show that a colloidal analogue of the MgCu2 Laves phase -- which can serve as a precursor of a photonic bandgap structure -- is a thermodynamically stable phase in a large region of the phase diagram. Our findings show a relatively large coexistence region between the fluid and the Laves phase, which is potentially accessible by experiments. Furthermore, we determine the sedimentation behaviour of the suggested mixture, by identifying several stacking sequences. Our work uncovers a new self-assembly path towards a photonic structure with a band gap in the visible region.

References in corpus (3)

• Assembly and Phase Transitions within Colloidal Crystals
• Floating nematic phase in colloidal platelet-sphere mixtures
• Sedimentation stacking diagram of binary colloidal mixtures and bulk phases in the plane of chemical potentials

Cited by in corpus (6)

• Self-Assembled Chiral Photonic Crystals From Colloidal Helices Racemate
• Gravity-induced phase phenomena in plate-rod colloidal mixtures
• Sedimentation of colloidal plate-sphere mixtures and inference of particle characteristics from stacking sequences
• Sedimentation path theory for mass-polydisperse colloidal systems
• Role of local assembly in the hierarchical crystallization of associating colloidal hard hemispheres
• Softness suppresses fivefold symmetry and enhances crystallization of binary Laves phases in nearly hard spheres