TeraGrid Computations Show Gyroid Defect Formation

Transatlantic Grid collaboration produces new understanding of liquid crystalline structures.

CHICAGO, August 18, 2006 — The Royal Society, the UK’s national academy of science, has published findings from computations performed by the TeraGyroid Project, a large-scale grid-computing project that linked more than 6,000 processors with a capability of 17 teraflops (trillions of calculations per second) at six different facilities on two continents. The resulting simulations are the first to show formation and evolution of realistic “gyroid” systems — structures that are a fascinating hybrid of liquid-solid physical features.

The paper, “Chirality and domain growth in the gyroid mesophase,” Proceedings of the Royal Society A (23 June 2006), is authored by theoretical chemist Peter Coveney, University College London, and his colleague Jonathan Chin. “Thanks to the TeraGrid,” said Coveney, “we were able to harness unprecedented resources and look at a problem that hadn’t been studied before. Liquid-crystal systems are scientifically important, and this study was possible only because multi-site grid resources were available.”

Liquid-crystal systems are widespread both in living systems — where they are thought to be a feature in certain lipid structures — and in the electronics display industry, where there’s much interest, says Coveney, in understanding how they operate: “We’ve developed tools that will allow this work to go forward.”

Co-led by Coveney and Bruce Boghosian of Tufts University, the TeraGyroid project used supercomputing, storage and visualization facilities at four TeraGrid sites, PSC, NCSA, SDSC and Argonne, along with the UK’s high-performance computing resources at Daresbury Lab and Manchester. The project, jointly funded by the National Science Foundation and the UK’s Engineering and Physical Sciences Research Council, won awards both at Supercomputing 2003 in Phoenix and at ISC2004, the European supercomputing conference.

The project aggregated computational and visualization resources for a series of simulations of a ternary “amphiphilic” mixture (oil, water & surfactant). The researchers steered the simulations to zero-in on a defect phase of the gyroid “mesophase” — a solid-like crystalline structure that forms in these liquid mixtures — and then used LeMieux, the Terascale Computing System at PSC, for a very large-scale (lattice-Boltzmann) simulation of this defect phase.

Because defect formation and dynamics in a gyroid was a problem that hadn't been addressed before, the project, says Coveney, necessitated developing new data-analysis tools. As they describe in the paper, a highlighted article at the Royal Society website, Coveney and Chin find that the self-assembly process of gyroids is characterized by diffusive motion.

The large simulations produced chiral gyroid structures, forming left-and-right-handed gyroidal domains via self assembly, a “defect” dynamics that prevents merger of separate domains into a “perfect” single crystal. Coveney and Chin developed measurements of curvature in the gyroids to analyze the behavior of domain walls, techniques that gave rise to the evidence of diffusive motion among gyroid grains.

The paper proposes several avenues for further work, including experiments to reproduce the chiral domains. “We’re in a region with these simulations,” says Coveney, “where nobody has studied these properties until now, and it’s gratifying that we’ve been able with computation to make predictions and invite experimentalists to take a look.”

The TeraGrid, sponsored by the National Science Foundation Office of Cyberinfrastructure, is a partnership of people and a comprehensive collection of resources and services that enables and accelerates discovery in U.S. science and engineering research. Through coordinated grid middleware, policy, and high-performance network connections, TeraGrid integrates a distributed set of high capability computational, data management and visualization resources to make U.S. research more productive. TeraGrid's Science Gateway collaborations and education and mentoring programs interconnect and broaden scientific communities.