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 a three-dimensional one to a planar flat structure. In another paper, they relate their discovery that gold in this size regime can be made magnetic through oxygenation of gold nanowires. They also found that up to a certain length, oxygenated gold nanowires behave as a conducting metal, but beyond that, they become insulators. This marks the first time on the nanoscale that such a metal-to-insulation transition has been found on the nanoscale. Both findings are important predictions that could some day be implemented as control parameters governing the chemical and physical material properties employed in nanotechnology.
The researchers focused their theoretical investigations on gold nanostructures because of the well known chemical inertness of gold in the bulk form, allowing one to maintain samples with minimal influence on the environment.
However, we again find that small is different, said Uzi Landman, Regents and Institute Professor, holder of the F.E. Callaway Chair, and director of the Center for Computational Materials Science, repeating a phrase that he coined and has used often for close to two decades. On the nanoscale, even gold becomes a potent catalyst, exhibiting new and surprising, chemical, mechanical, electrical and magnetic behavior, which could not have been extrapolated or predicted on the basis of our knowledge about this substance in the bulk form. Some of these systems may find technological uses in nanocatalysis and as chemical and electrical sensors, Landman added.
For the first study, which appears in the February 8 edition of Physical Review Letters, Landman and Research Scientist Bokwon Yoon performed first-principles quantum mechanical computer simulations of a 20-atom gold nanocl
|Contact: David Terraso|
Georgia Institute of Technology