The unique arrangement of carbon atoms in graphene provides a platform for testing new quantum phenomena that are difficult to observe in traditional materials. With its unusual electronic properties: its electrons can travel a long distance before scattering. Graphene is an extraordinary conductor. These properties also show other unique characteristics, making electrons seem to be close to the speed of light in the theory of relativity Like particles, they have strange properties that non-relativistic electrons do not possess. However, the position of atoms in the graphene lattice is fixed. In contrast, the spacing and arrangement of the lattice in artificial graphene can be set freely in a large interval. Such powerful multifunctional properties make artificial graphene a treasure in the eyes of researchers in the condensed matter field.

　　This research is led by experts in the engineering department of Columbia University specializing in nano-scale material manipulation. Through cooperation with colleagues from Princeton University, Purdue University and the Italian University of Science and Technology, the team redesigned the electronic structure of graphene in semiconductor devices for the first time. , Thus manufacturing a new type of "artificial graphene."

　　图|The etching pillar refers to the position of the quantum dots (red potholes) in the hexagonal lattice arrangement. When the spacing between quantum dots is small enough, electrons can move between them. (Source: DiegoScarabelli/Columbia University Engineering Department)

　　Aron Pinczuk, a professor of applied physics and physics in the Department of Engineering at Columbia University and the senior author of the study, said: “This landmark achievement redefines the highest level of condensed matter science and nanomanufacturing.” Although artificial graphene has been applied to optics , Molecules, and photonic grids, but these platforms lack the versatility that semiconductor processing technology can provide. The semiconductor artificial graphene device may become a platform for exploring new types of electronic switches, high-performance transistors, and even new methods of quantum state information storage.

　　ShalomWind, a researcher in the Department of Applied Physics and Applied Mathematics and co-author of the study, said: “This is a rapidly growing field of research. Many new phenomena that were previously unattainable have now been discovered. As we continue to explore artificial graphene based on electrical control With new devices, we can tap more potentials of graphene in the fields of optoelectronics and data processing."

　　"This work is actually a major advancement in artificial graphene technology. Previous theories had predicted that graphene-based electronic systems were artificially created and tuned with graphical 2D electron gas. But until this Columbia University study No one has successfully observed these properties in engineered semiconductor nanostructures.” said Steven G. Louie, professor of physics at the University of California, Berkeley. "Previous experiments on molecular, atomic and photonic structures can only represent systems with poor versatility and stability. This time nano-semiconductor structure provides new opportunities for exploring new science and its practical applications.webcam factory

　　Researchers use tools in traditional chip technology to develop artificial graphene in standard gallium arsenide semiconductors. They designed a layered structure so that electrons can only move within a very narrow layer, effectively creating a 2D layer. They used nanolithography and etching to characterize gallium arsenide: After characterization, gallium arsenide produces a hexagonal lattice that can confine electrons in the lateral direction. By placing these so-called "artificial atoms" close enough to each other (about 50 nanometers apart), these artificial atoms can interact in a quantum mechanical manner, similar to the way atoms share their electrons in a solid.

　　Compared with natural graphene, this kind of artificial graphene has many advantages: For example, researchers can adjust the electronic behavior by adjusting the honeycomb lattice. And because the distance between quantum dots is much larger than the distance between atoms in natural graphene, researchers can observe even more peculiar quantum phenomena under the action of a magnetic field.