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Physicists are accelerating the search for revolutionary atomic atomic materials



Graphene

This visualization shows the graphene layers used for the membranes. Credit: University of Manchester

Scientists at the University of Banja have taken an important step towards understanding the interaction between layers of thin atomic materials arranged in stacks. They hope their research will accelerate the discovery of new, artificial materials, leading to the design of electronic components that are much narrower and more efficient than anything known today.

The smallest is always the best in the world of electronic circuitry, but there is a limit to how far you can shrink a silicon component without overheating and shredding, and we are close to achieving that. Researchers are investigating a set of thin atomic materials that can be collected on shelves. The characteristics of each final material depend on both the choice of raw materials and the angle at which one layer is arranged on top of the other.

Dr Marcin Mucha-Kruczynski who led the research from the Department of Physics, said: “We have found a way to determine how strongly the atoms in different layers of a stack are joined together, and we have demonstrated the application of the idea for a structure made of graphene layers “.

Bath Study, published in Nature communications, is based on previous work on graphene ̵

1; a crystal characterized by thin sheets of carbon atoms arranged in a honeycomb pattern. In 2018, scientists at the Massachusetts Institute of Technology (MIT) discovered that when two layers of graphene accumulate and then warp relative to each other at a ‘magic’ angle of 1.1 °, they produce a material with superconductive properties. This was the first time that scientists had created a super-conductive material made entirely of carbon. However, these properties disappeared with the slightest difference in angle between the two layers of graphene.

Since the discovery of MIT, scientists around the world have tried to apply this ‘stacking and twisting’ phenomenon to other ultra-thin materials, putting together two or more different atomic structures in the hope of forming completely new materials. with special qualities.

“In nature, you can not find materials where each atomic layer is different,” said Dr. Mucha-Kruczynski. “Furthermore, two materials can normally only be placed in a specific way because chemical bonds must be formed between the layers. But for materials like graphene, only the chemical bonds between the atoms in the same plane are strong. The forces between the planes are known because “van der Waals interactions – are weak, and this allows the layers of material to twist in relation to each other.”

The challenge for scientists now is to make the process of discovering new materials, with layers as efficient as possible. By finding a formula that allows them to predict the outcome when two or more materials are aggregated, they will be able to direct their research immensely.

It is in this area that Dr. Mucha-Kruczynski and his associates at Oxford University, Peking University and ELETTRA Synchrotron in Italy expect to make a difference.

“The number of combinations of materials and the number of angles at which they can be distorted is too large to be tested in the laboratory, so what we can predict is important,” said Dr. Mucha-Kruczynski.

Researchers have shown that the interaction between two layers can be determined by studying a three-layer structure, where two layers are assembled as you can find in nature, while the third is distorted. They used angle-mounted photoshoot spectroscopy – a process in which strong light pulls electrons out of the sample to measure energy and momentum from electrons, thus providing insight into the properties of the material – to determine how strongly are two carbon atoms at a given distance from each other are joined. They have also demonstrated that their result can be used to predict the properties of other stacks made of the same layers, even if the curves between the layers are different.

The list of known atomically thin materials like graphene is growing all the time. It already includes dozens of inputs displaying a wide range of properties, from insulation to superconductivity, transparency in optical activity, fragility to flexibility. The latter discovery provides a method for the experimental determination of the interaction between layers of any of these materials. This is essential to anticipate the properties of more complicated stacks and to efficiently design new equipment.

Dr Mucha-Kruczynski believes it may be 10 years before new, collected and twisted materials find practical, everyday application. “It took a decade for graphene to shift from the lab to something useful in the ordinary sense, so with a hint of optimism, I expect a similar timeline to apply to new materials,” he said.

Based on the results of his recent study, Dr. Mucha-Kruczynski and his team are now focusing on twisted chimneys made from layers of transition metal dichalcogenides (a large group of materials containing two very different types of atoms – a metal and a chalcogen, such as sulfur). . Some of these shelves have shown attractive electronic behaviors which scientists are not yet able to explain.

“Because we are dealing with two radically different materials, the study of these stacks is complex,” explained Dr. Mucha-Kruczynski. “However, we are hopeful that in time we will be able to predict the properties of different stacks and design new multifunctional materials.”


Making assumptions from electronic curves


More information:
JJP Thompson et al, Determination of interatomic coupling between two-dimensional crystals using angle-resolved photosemission spectroscopy, Nature communications (2020). DOI: 10.1038 / s41467-020-17412-0

Provided by the University of Banja



citation: Physicists Accelerate Search for Revolutionary Atomic Atomic Materials (2020, August 11) Retrieved August 11, 2020 from https://phys.org/news/2020-08-physicists-revolutionary-artificial-atomic-materials.html

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