Supercomputer Helps Decipher Phenomena of Nanotubes

Nanotechnology researchers at Rice’s Center for Biological and Environmental Nanotechnology (CBEN) now have a supercomputer powerful enough to decipher the quantum phenomena of carbon nanotubes and other nanomaterials.

They plan to use the supercomputer to find new ways to use nanomaterials to treat and diagnose disease and to clean pollutants from the environment.

The 16-processor eServer p690, known as Regatta, was acquired through a Shared University Research award from IBM. It will provide the intense computing power needed to solve incredibly complex mathematical questions relating to molecular structure. Funded by the National Science Foundation, CBEN is the only academic research center in the world that is dedicated to studying the interaction of nanomaterials and living organisms and ecosystems.

Carbon nanotubes are single molecules of carbon that can contain millions of atoms arranged in hollow cylinders. Although these tubes are just one-billionth of a meter in diameter, they can stretch a millimeter or more in length. That’s analogous to a 15-mile-long garden hose.

Calculations on Regatta are showing that even small imperfections in the tubes can drastically affect their mechanical and electrical properties.
Part of the reason is that nanotubes are so small. With larger wires and circuits—even the transistors on today’s smallest microchips—quantum effects play a negligible role, meaning engineers can ignore them altogether. At the nanometer scale, however, the strange and counterintuitive forces of quantum mechanics play a critical part in determining electric conductance properties.

To find out exactly how the nanotubes will behave, a research team led by Gustavo Scuseria, the Welch Professor of Chemistry, uses the supercomputer to calculate precisely what happens as individual electrons and photons interact with carbon atoms in a nanotube. Even though Regatta can perform hundreds of millions of calculations per second, it takes up to a week to solve the equations describing a section of nanotube containing a few thousand atoms.

When the research is complete, IBM expects it will result in the development of linear scaling theories and algorithms that will represent a major step forward in theoretical molecular and biomolecular science.

—Jade Boyd