Roadrunner supercomputer simulates nanoscale material failure

October 29, 2009

Very tiny wires, called nanowires, made from such metals as silver and gold, may play a crucial role as electrical or mechanical switches in the development of future-generation ultrasmall nanodevices.

Making nanodevices work will require a deep understanding of how these and other nanostructures can be engineered and fabricated as well as their resultant strengths and weaknesses. How mechanical properties change at the nanoscale is of fundamental interest and may have implications for a variety of nanostructures and nanodevices.

A major limiting factor to this understanding has been that experiments to test how deform are many times slower than computer simulations can go, resulting in more uncertainty in the predictions than scientists would like.

"Molecular dynamics simulations have been around for a long time," said Arthur Voter of the Theoretical Division at Los Alamos National Laboratory. "But the simulations have never before been able to mimic the atomistic tensile strength of nanowires at time scales that even come close to experimental reality."

Using the "parallel-replica dynamics" method for reaching long time scales that Voter developed, members of Voter's team adapted their computer code to exploit the Roadrunner supercomputer's hybrid architecture, allowing them to perform the first-ever simulation of a stretching silver nanowire over a period of a millisecond, or one-thousandth of a second, a time that approaches what can be tested experimentally.

"Bigger supercomputers have made it possible to perform simulations on larger and larger systems, but they have not helped much with reaching longer times -- the best we can do is still about a millionth of a second. However, with the parallel-replica algorithm, we can utilize the large number of processors to 'parallelize' time," said Voter. "Roadrunner is ideally suited to this algorithm, so now we can do simulations thousands of times longer than this."

With this new tool, scientists can better study what nanowires do under stress. "At longer time scales we see interesting effects. When the wires are stretched more slowly, their behavior changes -- the deformation and failure mechanisms are very different than what we've seen at shorter time scales," said Voter.

Through these simulations, Voter and his team are developing a better understanding of how materials behave when they are reduced to the size scale of a nanometer, or one-billionth of a meter. "At this scale, the motion of just one single atom can change the material's mechanical or electrical properties," said Voter, "so it is really helpful to have a tool that can give us full atomic resolution on realistic time scales, almost as if we are watching every atom as the experiment proceeds."

Source: Los Alamos National Laboratory (news : web)

Explore further: Science at the petascale: Roadrunner supercomputer results unveiled

Related Stories

Scientists See Smallest-Ever Square Nanotube

February 20, 2009

(PhysOrg.com) -- Scientists have observed the smallest reported nanotube that has a square cross-section. The structure formed spontaneously and unexpectedly when silver nanowires were stretched and is a reminder that scientists ...

Physicists discover gold can be magnetic on the nanoscale

March 3, 2008

Physicists at the Georgia Institute of Technology have made important findings regarding gold on the nanoscale. They found that applying an electrical field on a surface-supported gold nanocluster changes its structure from ...

Seeing the unseen universe

August 1, 2006

A new method for incorporating astronomical observational data into computer simulations promises to be a significant advance in enabling future cosmological surveys aimed at understanding dark energy and dark matter. Dark ...

Scientists find why conductance of nanowires vary

February 5, 2007

A Georgia Tech physics group has discovered how and why the electrical conductance of metal nanowires changes as their length varies. In a collaborative investigation performed by an experimental team and a theoretical physics ...

Recommended for you

Atomic blasting creates new devices to measure nanoparticles

December 14, 2017

Like sandblasting at the nanometer scale, focused beams of ions ablate hard materials to form intricate three-dimensional patterns. The beams can create tiny features in the lateral dimensions—length and width, but to create ...

Engineers create plants that glow

December 13, 2017

Imagine that instead of switching on a lamp when it gets dark, you could read by the light of a glowing plant on your desk.

Faster, more accurate cancer detection using nanoparticles

December 12, 2017

Using light-emitting nanoparticles, Rutgers University-New Brunswick scientists have invented a highly effective method to detect tiny tumors and track their spread, potentially leading to earlier cancer detection and more ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.