Feb 24 2017
This is a spectrum of the three layer graphene as a function of magnetic field and density of electrons. (CREDIT: Biswajit Datta, Mandar Deshmukh)
As metals possess a large density of electrons, the wave nature of electrons can only be viewed if metallic wires measuring a few atoms in width are created.
However with graphene, a one-atom thick graphite, the density of electrons is a lot smaller and can be altered by making a transistor. Due to the low density of electrons, the wave nature of electrons, as illustrated by quantum mechanics, is easier to view in graphene.
Often in metals like copper, the electron is scattered every 100 nm, a distance approximately 1000 times smaller than the diameter of human hair, due to imperfections and impurities.
Electrons can travel greater distances in graphene, up to 10 μm, a distance approximately 10 times smaller than the diameter of human hair. This is attained when graphene is sandwiched between layers of boron nitride. The layers of boron nitride have few defects to hamper the electrons’ flow in graphene.
Once electrons travel great distances, indicating there are few flaws, one can notice the soft whispers of electrons "talking to each other". Decreasing of the flaws is similar to making a room silent to enable the soft whispers of electronic interactions to develop between several electrons.
In a research, led by PhD student Biswajit Datta, Professor Mandar Deshmukh's group at TIFR accomplished just this sort of silence allowing electronic interactions to be noticed in three layers of graphene. The research reveals a new type of magnet and offers insight on how electronic devices using graphene could be developed for elementary studies as well as applications.
This work detected the magnetism of electrons in three graphene layers at a low temperature of -272 °C. The magnetism of electrons develops due to the coordinated "whispers" between several electrons.