Theoretical physicists observe rare phenomenon in simple material for the first time
In the new research at the The University of Texas at Dallas have analyzed a infrequent occurance known as the quantum anomalous Hall effect in a very simple substance. Old test to analysis the effect, when a substance shows ferromagnetism and ferroelectricity concurrently only infrequently noticed the occurance in complex materials.
The quantum anomalous Hall effect was in bilayer graphene, a naturally occurring, two-atom thin layer of carbon atoms arranged in two stacked honeycomb-like lattices. The final end of the analysis, partially funded from the U.S. National Science Foundation, and this result is published in Nature.
Fan Zhang which are the theoretical physicist and also the co-author of the analysis said that - "When the infrequently quantum anomalous Hall effect was discovered formerly, the substances deliberate were complex. Otherwise, our material is comparably simple, since it just contains of two layers of graphene and shows naturally. "We predicted that there would be five families of states in bilayer graphene that participate with each other to be the ground state (the lowest-energy state in a quantum system). Four have been analyzed in the past. This is the last one and the most challenging to analyzed.”
The scientists observed eight types of ground states in bilayer graphene that shows the quantum anomalous Hall effect in the fifth family. By applying very little external electric and magnetic fields and maintaining the sign of charge carriers, the group was capable to change the state of the bilayer graphene. "We predicted, observed, elucidated and maintained a quantum anomalous Hall octet, where three striking quantum phenomena that are ferromagnetism, ferroelectricity and zero-field quantum Hall effect may coexist and even cooperate in bilayer graphene," said Zhang. "Now we know we can unify ferromagnetism, ferroelectricity and the quantum anomalous Hall effect in this simple substances."
The stability to precisely maintain the electronic properties of bilayer graphene could produced it a potential material for next generation quantum information uses or applications.