Entropy Alone Creates Complex Crystals From Simple Shapes

Entropy Alone Creates Complex Crystals From Simple Shapes

In a study that elevates the role of entropy in creating order, computer simulations show that hard tetrahedra spontaneously organize into complex quasicrystals.

Computer simulations of hard tetrahedra have uncovered a new type of quasicrystal —the first to be formed from hard or non-spherical particles. The findings, reported in the December 10 issue of Nature[1], show that particle shape is enough, by itself, to produce highly complex, ordered structures.  Sharon Glotzer and her colleagues have investigated the packing of tetrahedra using thermodynamic computer simulations, which allow the system to evolve naturally, in response to simulated compression, towards high-density configurations. The formation of an ordered but non-periodic structure (a quasicrystal) with twelve-fold symmetry is achieved by the self-organization of the tetrahedra into groups of five, and then of these groups into layers. In this way, an intricate structure is created from simple hard objects that interact only by excluding one another in space. 

More information from the UM News Service.

 

1.  “Disordered, quasicrystalline and crystalline phases of densely packed tetrahedra, “ Amir Haji-Akbari, Michael Engel*, Aaron S. Keys, Xiaoyu Zheng, Rolfe G. Petschek, Peter Palffy-Muhoray & Sharon C. Glotzer , Nature, December 2009.