University of Tokyo scientists have discovered why cooling sometimes causes liquid molecules to form disordered glasses, rather than ordered crystals.
Researchers Hiroshi Shintani and Hajime Tanaka have developed a two-dimensional model of a simple molecular system that can be tuned continuously from one state to another, including from a crystal to a plastic crystal to a glass containing crystalline clusters.
The authors take a liquid model whose molecules would naturally form an ordered crystalline structure and add a potential favoring formation of disordered clusters of five-fold crystals. The resulting frustration in the system can then be controlled to alter the degree to which the ordered structure is formed, against the number of disordered clusters within the liquid.
They say they are able to show the liquid naturally forms both types of structure in a dynamic system. The presence of the domains provides a natural explanation for the dramatic slowing down of the dynamics in a glassy system.
The research is explained in the March issue of Nature Physics.
Copyright 2006 by United Press International
Related stories:
Physicists Transmit Light through Opaque Materials
No matter how thick an opaque "scattering material" is, physicists have shown how to weave light through tiny open channels in the material, so that the light passes through on the other side.
Argonne scientists discover new class of glassy material
(PhysOrg.com) -- Scientists at U.S. Department of Energy's Argonne National Laboratory are dealing with an entirely new type of frustration, but it's not stressing them out.
Atomic-Level Mechanisms of Phase-Change Memory Materials Revealed
Scientists from the University of Cambridge in the UK have uncovered the atomic-level interactions that occur when a class of “phase-change” memory materials stores information. Their work, reported in the March 23 online edition of
Nature Materials, may open up new avenues for research into these fascinating materials, possibly leading to a new generation of “super” memory materials for electronic devices.
Atoms Fly Apart in Direct Crystal Melting
Using an intense laser and ultra-fast x-rays, Stanford Synchrotron Radiation Laboratory (SSRL) researchers have observed the atomic events involved in rapid crystal melting.
Researchers clear way to stronger glass
Look at your window - not out it, but at it. Though the window glass looks clear, if you could peer inside the pane you would see a surprising molecular mess, with tiny particles jumbled together any which way.
Modeling Mineral Formation with X-rays
Some of the hardest and sturdiest materials aren’t made in the factory; they’re made inside the bodies of animals. Biominerals are commonly used for support and protection, forming in teeth, bones, and shells in animals ranging from humans to mollusks. The cells in an animal’s body have special ways of controlling the sizes and shapes of these mineral compounds and incorporating organic materials into the mix, making many materials that are stronger, harder and more wear-resistant than rocks.
Liquid Alloy Shows Solid-Like Crystal Structure at Surface
A substance used in nanotechnology contains unusual structures at its surface, a team of researchers led by Oleg Shpyrko, Distinguished Postdoctoral Fellow, has learned. The research results, developed at Argonne's Center for Nanoscale Materials, were published in the journal
Science.
Liquid alloy shows solid-like crystal structure at surface
A substance used in nanotechnology contains unusual structures at its surface, a team of researchers led by Oleg Shpyrko, Distinguished Postdoctoral Fellow at the U.S. Department of Energy's Argonne National Laboratory has learned.