Graphene-The "Magic" Material

With a Simple Twist, a “Magic” Material Is Now the Big Thing in Physics by David H. Freedman, published in Quanta Magazine is an enticing article which explains the recent discoveries surrounding a material called Graphene. Graphene is a one-atom thick sheet of carbon in a hexagonal lattice. This material has many unique properties. It is roughly 200 times stronger than steel while also being a great conductor of heat and electricity. The biggest recent breakthrough in the field of solid-state physics was made by Jarillo-Herrero who in 2018 found superconducting properties in graphene when taking two sheets and placing them on one another then rotating them slightly. A superconductor is any material that can conduct electricity without heat, sound, or any other kind of energy being dissipated from the material. The difficulty with superconductors is the need for the material to be very cold in order to superconduct.
Graphene is the next step because it is a path toward higher-temperature superconductivity. This material if perfected as a superconductor will revolutionize many industries. The most important observation was the angle of twist in the bi-layered graphene has to be 1.1 degrees for superconductivity to occur.
Antonio Castro Neto another physicist, who in 2007 suggested the possibility of creating different properties when pressing two misaligned layers of graphene together was quite surprised at Jarillo-Herrero’s findings. Castro Neto said of the findings, “It would have been crazy to predict superconductivity based on what we knew but science moves forward not when we understand something, it’s when something totally unexpected happens in experiment.” In 2011, Allan MacDonald, a theoretical physicist, was studying the behavior of bi-layered graphene an the “magic angle” and found that a free-flowing electron could move in between the two sheets without gain or loss of energy at 1.1 degrees. After his paper was published not many experimenters tried to test his theories out as they saw it as being too simple of an explanation. Most shied away from it and moved onto other research but not Jarillo-Herrero. He was adamant that there was more to graphene than they had found. He kept trying to improve the process of creating the sheets of graphene and the way that they sustain the required angle. Then a student of his in 2014 showed him a graphene device that when subject to an electric field became an insulator and when the strength of the field was increased its properties changed from insulator to superconductor. They spent six months secretly recreating the results and getting their measurements perfected. Then they submitted their paper for review and publishing. In March 2018, when the paper was published by Nature, they discussed their findings with the rest of the physics community.
The most important aspect is that the physics community is learning more about the properties of superconductors from their experimental findings. With a small tweak of an external electric field on the bi-layered graphene they are able to change the properties of the graphene from conducting to insulating to superconducting. The changing of its conducting properties due to an electric field shows that the fee electrons are being slowed to a near halt, and when that happens it allows the electrons to pair up and create a kind of electron superfluid. That superfluid they now believe is the main feature of all superconductors and is most likely why they need to be at a low energy state or really cold to work.
The work done by these physicists is truly amazing in the field of superconductors. But most importantly it is a breakthrough that will lead to more breakthroughs which in turn will revolutionize every industry and change daily life for the better. To create a room temperature superconductor that can also be mass manufactured will have important effects on the world. Graphene has many broad applications already and when it becomes used as a superconductor it will be ever more important. Batteries, transistors, computer chips, energy generation, supercapacitors, DNA sequencing, water filters, antennas, touchscreens (for LCD or OLED displays), solar cells, Spintronics-related products are all areas that can be improved by graphene already. If we can get the graphene to be a superconductor at room temperature then we will be able to improve even more. In Michio Kaku’s book, Physics of the Future, he talks about how superconductors will help to improve our future. He explains how they will allow us to create advanced quantum computers which will be useful for many complex calculations and scientific advancements. Another important achievement will be the ability to create a hand-held MRI machine utilizing superconductors. This will lower costs in general and allow for more accurate use. Graphene being an extremely strong material will also be used for building and machinery.
Kaku, Michio. Physics of the Future. 1st ed., New York, Anchor Books, 2011.