Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 34, 2012
Previous Article Next Article

Phase diagram of colloidal hard superballs: from cubes via spheres to octahedra

Author affiliations

Abstract

For hard anisotropic particles the formation of a wide variety of fascinating crystal and liquid-crystal phases is accomplished by entropy alone. A better understanding of these entropy-driven phase transitions will shed light on the self-assembly of nanoparticles, however, there are still many open questions in this regard. In this work, we use Monte Carlo simulations and free-energy calculations to determine the phase diagram of colloidal hard superballs, of which the shape interpolates between cubes and octahedra via spheres. We discover not only a stable face-centered cubic (fcc) plastic crystal phase for near-spherical particles, but also a stable body-centered cubic (bcc) plastic crystal close to the octahedron shape. Moreover, coexistence of these two plastic crystals is observed with a substantial density gap. The plastic fcc and bcc crystals are, however, both unstable in the cube and octahedron limit, suggesting that the local curvature, i.e. rounded corners and curved faces, of superballs plays an important role in stabilizing the rotator phases. In addition, we observe a two-step melting phenomenon for hard octahedra, in which the Minkowski crystal melts into a metastable bcc plastic crystal before melting into the fluid phase.

Graphical abstract: Phase diagram of colloidal hard superballs: from cubes via spheres to octahedra

Back to tab navigation

Supplementary files

Additions and corrections

Article information


Submitted
06 Apr 2012
Accepted
01 Jun 2012
First published
09 Jul 2012

Soft Matter, 2012,8, 8826-8834
Article type
Paper

Phase diagram of colloidal hard superballs: from cubes via spheres to octahedra

R. Ni, A. P. Gantapara, J. de Graaf, R. van Roij and M. Dijkstra, Soft Matter, 2012, 8, 8826
DOI: 10.1039/C2SM25813G

Social activity

Search articles by author

Spotlight

Advertisements