The fractional quantum Hall effect: the newly found quantum states in double layer graphene

An image to illustrate that new quantum states have been found in double layer graphene, known as the fractional quantum Hall effect

Quantum states of matter, now known as the fractional quantum Hall effect, have been in found in double layer graphene.

The previously unknown quantum states arise in two dimensional nanomaterial of double layer graphene due to the interactions of electronics within and across the layers. The new states have been called the fractional quantum Hall effect by the researchers at Brown and Columbia universities.

The quantum states of double layer graphene

Qianhui Shi, the paper’s co-first author and postdoctoral researcher at Columbia, explained: “Apart from the interlayer composite fermions, we observed other features that cannot be explained within the composite fermion model. A more careful study revealed that, to our surprise, these new states result from pairing between composite fermions. Pairing interaction between adjacent layers and within the same layer give rise to a variety of new quantum phenomena, making double-layer graphene an exciting platform to study.”

New physics: the potential applications of the quantum states

“The findings show that stacking 2D materials together in close proximity generates entirely new physics,” said Jia Li, assistant professor of physics at Brown, who initiated this work while a post-doc at Columbia working with Cory Dean, professor of physics, and Jim Hone, professor of mechanical engineering. “In terms of materials engineering, this work shows that these layered systems could be viable in creating new types of electronic devices that take advantage of these new quantum Hall states.”

Dean adds: “Once again the incredible versatility of graphene has allowed us to push the boundaries of device structures beyond what was previously possible.The precision and tunability with which we can make these devices is now allowing us to explore an entire realm of physics that was just recently thought to be totally inaccessible.”

The research is published in the journal Nature Physics.

Source: Columbia University School of Engineering and Applied Science

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