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Did you know that the structure of double-layer graphene can affect its electronic properties? How does it work?
Double-layer graphene is a special material composed of two layers of graphene. Since this material was first reported in 2004, it has become one of the most talked about topics in the fields of materials science and applied physics. The researchers found that the structure of double-layer graphene has a significant impact on its electronic properties, which not only changes the material's fundamental behavior but also opens up potential new technological applications, such as in electronic devices and energy storage devices.
Structure and characteristics
The most common structural form of double-layer graphene is the AB or Bernalli stack, in which half of the atoms are located above the center of the lower graphene hexagon, while the other half is exactly aligned with the atoms of the lower layer. Compared with the AA stack structure, the AB stack structure is more stable and its electronic properties are also different.
Research shows that the binding energy of the AB stack structure is as high as 17.7(9) meV per atom, while the AA stack is 11.5(9) meV per atom, which means that the AB stack structure is more stable, which in turn affects its electronic conduction. sex.
Adjustable band gap
Double-layer graphene has a band gap of zero and exhibits semi-metallic properties. However, studies have shown that by applying an electric field, it is possible to introduce a tunable band gap into bilayer graphene. This theory was experimentally verified in 2009. Such band gap control not only enhances the application potential of double-layer graphene in electronic devices, but also opens up its application in quantum devices.
The emergence of complex states
In 2014, researchers confirmed the emergence of more complex electronic states in double-layer graphene, especially the fractional quantum Hall effect, and showed that it can be controlled by an electric field. These findings are of great significance for the future application of double-layer graphene technology in topological materials and quantum computing.
Superconductivity and twisted bilayer graphene
In 2018, an MIT research team discovered that superconductivity occurs when the rotation angle of double-layer graphene is adjusted to 1.1°. This discovery challenged scientists' imagination of graphene applications. This has also triggered a research boom in "twisted electronics", which will have a revolutionary impact on the development of new electronic devices in the future.
Jarillo-Herrero said that in the future, one can "imagine using graphene to make switchable superconducting transistors. Such technology will bring many new possibilities for quantum devices."
Potential applications
The high conductivity and low band gap of double-layer graphene make it ideal for use in field-effect transistors (FETs) and tunnel field-effect transistors. In addition, its application in lithium-ion batteries is also particularly important. Because the structure of double-layer graphene can significantly enhance the diffusion of lithium ions, the charge and discharge efficiency of lithium-ion batteries is improved.
Summary and Outlook
The discovery and research of double-layer graphene not only promotes the development of materials science, but also provides theoretical basis and application potential for new electronic devices. As research on double-layer graphene deepens, more unexpected applications may emerge in the future. Can you imagine how future technology will change our daily lives?
