The Butterfly Effect: Combining Black and White Graphene Alters Material's Electrical Properties

A combination of black and white graphene overcomes the electrical conductivity problems of the "wonder material," researchers say.

Several researchers are trying to use graphene sheets to make lighter, bendable electronics of the future. However, a major problem with the material is that it lacks a band gap. In simpler terms, graphene's electrical conductivity can't be switched on and off.

Scientists have always failed to control graphene's electrical conductivity, which has led to the discovery of several other materials that can advance electronics. However, researchers at the University of Manchester say that it isn't time to write graphene off yet.

Placing a layer of boron nitride or white graphite under a layer of regular, black graphene can change the material's electronic properties.

The research is one of the several such studies that are trying to combine graphene with other materials to control the material's electronic properties.

Hofstadter's Butterfly                                                                           

University of Manchester scientists used capacitance measurements to analyze the changes brought by the multi-layered arrangement of black and white graphene. The team found that when they applied magnetic field to this system, they obtained numerous replicas of the original graphene spectrum.

Hofstadter butterfly effect is well-known and has been previously demonstrated in graphene structure. However, this is the first time that researchers have observed well developed replica spectra in the material.

Researchers also found that the white-black graphene structure alters graphene's ferromagnetic properties. Usually, graphene becomes magnetic only when the magnetic fields are high. But, in the new bilayer structure, the material displays unusual ferromagnetic properties depending on the replica state, according to a news release.

"It is really a new nice electronic system both similar to and different from graphene. We expect many more surprises. Let us first understand what it is and then we start talking about possible applications," said Dr Artem Mishchenko, one of the study authors.