Researchers Create Glass Just 3 Atoms Thick 160
sciencehabit writes "Researchers have created the world's thinnest pane of glass. The glass, made of silicon and oxygen, formed accidentally when the scientists were making graphene, an atom-thick sheet of carbon, on copper-covered quartz. They believe an air leak caused the copper to react with the quartz, which is also made of silicon and oxygen, producing a glass layer with the graphene. The glass is a mere three atoms thick — the minimum thickness of silica glass—which makes it two-dimensional. The team notes that the structure 'strikingly resembles' a diagram drawn by a glass theorist attempting to unravel its structure back in 1932. Such ultra-thin glass could be used in semiconductor or graphene transistors." See Nano Letters for an abstract (and another picture) to the paywalled article.
Re:Two-dimensional? (Score:5, Informative)
It's not two dimensional if it has a measurable thickness, which you stated in that same sentence. Unless you have a different definition of "two dimensional" than the rest of us.
Someone posted that same criticism in the article. Here is someone's reply (again, from the comments). I'm not a chemist or physicist, but what they say sounds reasonable:
Hi Heather - fair enough, it's not 2D as in the mathematical concept, but 2D has a physical meaning as well - the thinnest version of a material. Because the silicon and oxygen atoms don't lay flat, glass needs a minimum of three layers of atoms (two silicon and one oxygen) to form a chemically stable sheet. Inside some of these technically 3D ultrathin materials, the electrons behave like their world is two dimensional.
Re:Also? (Score:4, Informative)
http://en.wikipedia.org/wiki/Quartz [wikipedia.org] "It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2."
http://en.wikipedia.org/wiki/Silicon_dioxide [wikipedia.org] "Silica is used primarily in the production of glass for windows, drinking glasses, beverage bottles, and many other uses."
Glass and quartz.
Re:Two-dimensional? (Score:5, Informative)
I believe they're calling it two dimensional because it's the minimum thickness possible, so for practical purposes, the thickness is equal to a single point. You can argue semantics all you want, but if you were to "travel" on a glass sheet, you would only be able to go along the X axis or Y axis - there is no ability to travel along a Z axis that is only a single point.
Re:Two-dimensional? (Score:0, Informative)
Unless you have a different definition of "two dimensional" than the rest of us.
You're talking about euclidean space, they're talking about crystal structure. They've built an n * n * 1 array of molecules, if you like. If you can't spot the isomorphism between that and an n * n array, you might want to steer clear of any IQ tests...
Re:Two-dimensional? (Score:4, Informative)
The glass is a mere three atoms thick — the minimum thickness of silica glass—which makes it two-dimensional.
It's not two dimensional if it has a measurable thickness, which you stated in that same sentence. Unless you have a different definition of "two dimensional" than the rest of us.
Your question can be answered in two ways. First, in the materials science community, it's common to denote a material or chunk of material that has a very high aspect ratio, for instance very large in one or two dimensions and small in size on the order of the atomic scale in the remaining directions as effectively one- and two-dimensional. In fact, quantum dots are thought of in materials science as generally zero-dimensional, even though they most certainly have more than one atom (and even if they comprised a single atom, the electron cloud extends in three dimensions). So, as far as the materials science and electron microscopy fields are concerned, this is two-dimensional.
Second, you tend to get your paper published in fancier journals and grab more headlines by having sensational things such as 2D (in this case) or quantum or some such buzzword in your title these days.
Re:Two-dimensional? (Score:5, Informative)
From a post by the author at TFA:
"Inside some of these technically 3D ultrathin materials, the electrons behave like their world is two dimensional."