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Two-dimensional magnetism has long intrigued and motivated researchers for its potential to unleash new states of matter and their utility in nano-devices.
The excitation is partly motivated by predictions that the magnetic moments of the electrons – called "spins" – could no longer be aligned in perfectly clean systems. This improvement in excitation forces could trigger many new states of matter and allow new forms of quantum computing.
A major challenge has been the successful manufacture of perfectly clean systems and their incorporation into other materials. However, for more than a decade, materials known as "van der Waals" crystals, held together by friction, have been used to isolate thick layers of an atom leading to many new effects and physical applications.
Researchers at Boston College, the University of Tennessee, and the Seoul National University recently expanded this class to include magnetic materials and could offer one of the most ambitious platforms to date. in scientific efforts to study and manipulate the phases of matter at the nanoscale. , write in the last issue of the journal Nature.
Two-dimensional magnetism, the subject of theoretical exploration and experimentation over the past 80 years, is experiencing a resurgence through a combination of relatively abundant and easily manipulated materials and compounds, according to Kenneth Burch, associate professor of Boston College. a first author of the article "Magnetism in two-dimensional van der Waals materials".
The most frequently cited example of these materials is graphene, a crystal built in uniform layers of atomic thickness. A procedure as simple as applying a Scotch tape to the crystal removes a single layer, providing a thin, uniform section that serves as a platform for creating new materials with a range of properties physical properties that can be manipulated.
"What's amazing with these 2D materials is that they're so flexible," Burch said. "Because they're very flexible, they give you a lot of possibilities, you can make combinations you could not have dreamed of before, you can just try them out, you do not have to spend that huge amount of time, Money and machines to try A student who works with cassettes assembles them.This adds to this exciting opportunity that people have long dreamed of, to be able to conceive of these new phases of matter. "
At this unique layer, the researchers focused on spin, which Burch calls the "magnetic moment" of an electron. While the charge of an electron can be used to send two signals – either "off" or "on", the results are represented by excitations at zero or a spin – offering multiple control and measurement points, an exponential expansion of the potential to report, store or transmit information in the smallest of spaces.
"One of the big efforts now is to try to change the way we calculate," Burch said. "Now, we record whether the electron charge is present or not.Since each electron has a magnetic moment, you can potentially store information using the relative directions of those moments, which are more related to a multi-point compass.You do not only get a one and a zero, you get all the values in between. "
Potential applications are in the areas of new "quantum" computers, sensing technologies, semiconductors or high temperature superconductors.
"Our view is that the focus has been on devices and that we are trying to use these 2D materials to make these new devices, which is extremely promising," Burch said. "But what we emphasize is that magnetic 2D atomic crystals can also realize the dream of engineering these new phases – superconducting, magnetic or topological phases of matter – which is really the most more exciting, theorems that have existed for 40 years.These new phases would find applications in different forms of computer science, be it spintronics, the production of high-temperature superconductors, magnetic and optical sensors, and the like. topological quantum computing.
Burch and his colleagues – David Mandrus of the University of Tennessee and the Je-Geun Park at the Seoul National University – set four major directions for research on van der Waals magnetic materials:
- Discover new materials with specific features. New materials with isotropic or complex magnetic interactions could play an important role in the development of new superconductors.
- These new materials can also lead to a deeper understanding of the fundamental problems of condensed matter physics, thus constituting a unique platform for experimentation.
- The materials will be tested to determine if they could become unique devices, capable of providing new applications. The two-dimensional structure of these materials makes them more receptive to external signals.
- These materials have quantum and topological phases that can potentially lead to exotic states, such as quantum spin liquids, skyrmions, or new iterations of superconductivity.
Germano Iannacchione, a National Science Foundation (NSF) Program Officer who oversees the grants to Burch and other materials scientists, said the co-authors offered the wider community some scientific ideas to guide a dynamic domain that goes beyond the boundaries of materials research.
"Magnetism in Van Der Waals 2D materials has become a dynamic field of study," said Iannacchione. "Its researchers have evolved from highly specialized researchers to statesmen who manage a field and expand applications to as many channels as possible.This analysis describes the multiplicative aspect of a regular search. Targeted and sometimes risky, opening up new frontiers and offering considerable potential for applications in quantum and spintronic computing. "
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