What is making waves in nanoscience? If you were to write that sentence using a pencil, you most likely would create a structure that is currently exciting many scientists.
The structure is called graphene and is created when a thin layer of atoms are peeled off a chunk of graphite. Graphite is, of course, the stuff pencils are made from, but it is also an interesting material for many reasons. First, it is one of a small family of materials that are intrinsically layered. Imagine that you are holding a net or a fine veil. For the clearest image, the wholes in the net should be hexagonal. Now imagine shrinking that net down such that each knot in the net is just a single atom of carbon. Lay the carbon net carefully on the table and then place your next atomic net on top of it. Once you’ve added your 100,000th layer, you have something that you can see since it is now about the thickness of a hair. This stack of nets is the structure of graphite and a single net is called graphene. Although floppy, this net is actually quite stiff–much stiffer than diamond. But, that is not what currently interests researchers. What really excites them is the way electrons move through graphene.
Now, I have been thinking about how to describe their behavior to someone who is not familiar with solid state physics (my own familiarity needs some brushing up too) and the best I can do is the following. Think of a pinball game with the ball at the top. Since the board is tilted, the ball always moves downward but is bounced off all the different bumpers and obstacles. When an electron moves through normal materials, it is like that pinball–always being bounced off different defects in the material which slow it. Electrons in graphene, however, act more like “ghost” pinballs. They tend to move through obstacles and not be bounced everywhere. Also, they do not have an effective mass when moving around.
There are many other anecdotes that could be shared, but the real point is that this is the first time scientists can study certain types of behavior. It had been thought that the only way to see some of these effects was to buy a much more expensive atom-smasher or to travel perilously close to a black hole. Now, these experiments can be done much more cheaply, allowing many more people to study it. And that is good, because Science is something we do together.
Why waves then? Well, electrons at this scale always act as waves…or particles (it depends how you ask).
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Who posted this?
Paul Sheehan. I’m a scientist working for the US Government who lives in Washington, DC.
Who sent me the challenge?
Nadja Pass. WoW2.
My challenge goes out to:
Paul has now passed on the challenge. Check back – or subscribe to this blogs rss-feeds – for the next Wave of Wisdom…
[...] et smut til D.C. under “The cherry blossom festival” for at besøge min gode ven Paul og hans familie midt i mylderet af blomstrende kirsebærtræer ved Jefferson [...]