Volume 2 Issue 9, September 2006
The Klein Paradox enables a relativistic electron to pass straight through a potential barrier of at least twice its rest mass, as if the barrier were not even there. Such behaviour, which is just one of the many counterintuitive consequences of the Dirac equation, is usually expected to occur under only the most extreme of circumstances, such as in the vicinity of a black hole. But Mikhail Katsnelson and colleagues suggest that analogous conditions to those that support this paradox exist in a single sheet of graphene. They predict that when the massless Dirac fermions that carry charge in graphene encounter a square barrier at normal incidence, they too will pass through it with perfect efficiency. Moreover, analysis of related effects at oblique incidence and in bilayer graphene suggests this behaviour could be used for device applications.
Editorial
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