Results tagged “physics”

Graphene is in the news again, with the announcement that researchers at the University of Manchester have demonstrated (PDF) a graphene-based single electron transistor. That's an exciting development, but the hype machine immediately went completely out of control. Wired declared that Moore's Law is saved, while less restrained corners of the blogosphere announced that "silicon is out, carbon is in".

Well, not exactly. First of all, most of the devices in question were measured at 0.3 K, not exactly a practical temperature for commercial electronics. Second, the whole point of the referenced paper is that the behavior of Dirac fermions(*) under such extreme confinement is chaotic. Somehow I don't think the CMOS industry is quite ready for design models based on quantum statistics. And finally, all of these experiments used mechanically exfoliated graphene, which is a fancy way to say "we rubbed a pencil lead on a silicon wafer and told a grad student to find the graphene flakes." Again, not a commercially viable strategy.

This is not to denigrate the very interesting work being done at the University of Manchester and elsewhere. Graphene is an excellent system for important studies of very fundamental physics. But researchers have a long long way to go to develop a commercializable process, much less make a noticeable dent in the silicon market. Let's keep our expectations in line with reality, shall we?

(*) What's a Dirac fermion? Did I mention that carriers in graphene don't behave like normal electrons?

Quasicrystals are one of those topics that I've always been intrigued by, but never had a chance to really investigate. (Quasicrystals are materials with aperiodic ordering: x-ray diffraction shows that they have internal symmetry, but they lack the translational symmetry that true crystals have.) Now they've given me a reason to find the local engineering library: work to be published in the Journal of the American Mathematical Society shows that the standard equations used to calculate electrical conductivity don't work for quasicrystals. The very idea makes my head hurt if I think about it too much. Clearly one for the research file.

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