Unexpected metal–insulator transition in graphene/boron nitride heterostructures

The Nobel winners for the discovery of graphene (or better, for the isolation of graphene) Andre Geim and Kostya Novoselov, joint with their team at the University of Manchester,  have made a new step along the road for graphene electronics. They have encapsulated ultra-high-quality graphene between two layers of another two-dimensional material, the boron nitride, in such a way to exclude interactions with environment, keeping the graphene as pure as in the pristine form. A second layer of graphene is used to control the electronic properties of the sandwiched graphene. A structure like that build-up by the Universty of Manchester’s team, could be able in the future to replace silicon chips in computers.

But the researchers found also something unexpected. Anderson localization, as it is well known, is a metal-insulator transition induced  by disorder in solids at low temperatures. On the other hand high-quality graphene is not only the thinnest and strongest material in the world, but also the most conductive. Well, said this, they have reported “a strong localization and the corresponding metal-insulator transition in ultra-high-quality graphene”. In other words, the metallic and pure graphene becomes insulator. The transition to insulator in ordered rather than disordered materials is a unique occurrence that unveils some new physics.

Abstract of the original paper
http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys2114.html#/access

Preprint
http://arxiv.org/ftp/arxiv/papers/1107/1107.0115.pdf

Philip Warren Anderson was born in Indianapolis (Indiana, USA) on 1923

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About Francesco Buonocore

Francesco Buonocore is an Italian solid state theoretical physicist, staff scientist of the Italian government agency ENEA. Francesco likes Physics, thinking about Physics and how Physics and life are related.
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