Electrons in Sharper Focus

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Science  02 Mar 2007:
Vol. 315, Issue 5816, pp. 1189d
DOI: 10.1126/science.315.5816.1189d
CREDIT: CHEIANOV ET AL.

The fabrication of metamaterials that give rise to negative refractive index for electromagnetic radiation has been used to image objects smaller than the conventional diffraction limit, and such materials hold the promise of creating the “perfect lens” that could achieve extremely fine focusing. Cheianov et al. (p. 1252; see the Perspective by Pendry) carry over the principle of the perfect lens and negative refraction to electron flow. They show theoretically that a graphene sheet, which makes electrical contacts such that one side is p-type and the other n-type, should be able to focus the flow of electrons as they pass through the pn-junction. They argue that such an effect could lead to novel applications in electron optics such as electron-beam splitters and lenses.

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