How Twisted Graphene Became the Big Thing in Physics

The lab produced dozens of twisted bilayer graphene “Devices,” as researchers call them, but none of them showed significant evidence of electron correlation.

The sudden jumps in twisted bilayer graphene – from conducting to insulating to superconducting – with just a tweak of an external electric field indicate that free electrons are slowing to a virtual halt, notes physicist Dmitri Efetov of the Institute of Photonic Sciences in Barcelona, Spain.

Said MacDonald, is the small number of electrons that seem to be doing the heavy lifting in magic-angle twisted bilayer graphene – about one for every 100,000 carbon atoms.

MacDonald points out, for example, that some of the insulating states in twisted bilayer graphene appear to be accompanied by magnetism that arises not from the quantum spin states of the electrons, as is typically the case, but entirely from their orbital angular momentum – a theorized but never-before-observed type of magnetism.

Semiconductors and transitional metals can be deposited in twisted layers and are seen as good candidates for correlated physics – perhaps better than twisted bilayer graphene.

Having burst far out into the lead of the twisted bilayer graphene field in stunning fashion, Jarillo-Herrero isn’t sitting back and waiting for others to catch up.

Such hopes ultimately pan out, for now the excitement in twisted bilayer graphene seems only to be building.

This article was summarized automatically with AI / Article-Σ ™/ BuildR BOT™.

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