In 2004, two physicists at the University of Manchester used tape to strip graphene of a single atom thickness from the layered graphite for the first time.
Since then, several experimental groups have quickly devoted themselves to twisting the properties of double-layer graphene. Under research.
Recently, an international research team led by the University of Manchester in the United Kingdom has developed a new nanomaterial that can reflect the “magic angle” effect originally found in the complex man-made structure-twisted double-layer graphene.
New research shows that the special topological structure of rhombohedral graphite effectively provides an inherent “distortion” and therefore provides an alternative medium to study effects such as changes in superconductivity. “This is an interesting alternative method that can replace the very popular research on ‘magic angle’ graphene.” said Andre Geim, one of the authors of the study.
Scientists stacked one piece of graphene on top of another and twisted it into a “magic angle”, turning it into a superconductor. The interaction in the double-twisted layer graphene is extremely sensitive to the twist angle, so it is extremely difficult to manufacture a device with the required accuracy. People must find a sufficiently uniform device to study the physics involved. The new research uses diamond-shaped graphene to open a new door to the precise manufacturing of superconducting devices. The Mishchenko team has now observed that strong electron-electron interactions occur in the weakly stable rhombohedral graphite-the form of stacking graphene layers is slightly different from the stable hexagon.
The Manchester University team has been studying diamond-shaped graphite films for many years and has developed advanced technologies that can produce high-quality samples. In the new study, the researchers modified their technology to protect the fragile and unstable form of graphite stacks. The researchers imaged a sample containing 50 layers of graphene and used Raman spectroscopy to confirm that the stacking order of the materials remained intact. Then, they used traditional methods to measure the electron transport characteristics of the sample—by recording the resistance of the material as it changes temperature and the strength of the magnetic field applied to it.
The researchers said that the energy gap in the surface state of rhombohedral graphite can be opened by applying an electric field. This gap opening is accompanied by a hysteresis behavior of material resistance, which means that different electronic gap phases are divided into domains-a typical feature of strongly correlated materials.
The article is originally published at mis-asia.