NIST team reveals new graphene QDs structure

NIST physicists have spatially and magnetically confined electrons within graphene atoms into cake-like nanostructures, proving theoretical speculations, and promising applications for quantum computing. It was said that the experiment “confirms how electrons interact in a tightly confined space according to long-untested rules of quantum mechanics. The findings could also have practical applications in quantum computing".

Scientists have to confine quantum dots in space to work with them, but the NIST researchers thought of applying a magnetic field to see how electrons orbiting quantum dots would behave. Using a scanning tunneling microscope, the team found that electrons packed together more and arranged themselves into concentric rings that alternate between conducting and insulating energy levels, shaped like a tiered cake.

“This is a textbook example of a problem — determining what the combined effect of spatial and magnetic confinement of electrons looks like — that you solve on paper when you’re first exposed to quantum mechanics, but that no one’s actually seen before… In previous experiments using other materials, quantum dots were buried at material interfaces so no one had been able to look inside them and see how the energy levels change when a magnetic field was applied,” said NIST’s Joseph Stroscio.

According to the research paper, the new experiment also opens the door to probe the potential of graphene as a relativistic quantum simulator. Particles of a “quantum-relativistic matter” move at speeds near to the speed of light, or what’s called “relativistic speed”.

Electrons within graphene atoms have this property and exhibit photon-like behavior as if they were massless, and the present study from NIST creates “a table-top experiment to study strongly confined relativistic matter.”

However, the magnetic confinement of electrons doesn’t work in a room-temperature setting. For the emerging phenomenon to take place, NIST researchers will have to subject the graphene quantum dots to near absolute zero temperatures.

Posted: Sep 02,2018 by Roni Peleg