Unique quantum material could enable ultra-powerful compact computers

Unique quantum material could enable ultra-powerful compact computers

Unique quantum material could enable ultra-powerful compact computers

Chromium sulfide bromide crystallizes in thin layers that can be separated and stacked to create nanoscale devices. Columbia researchers have discovered that the electronic and magnetic properties of this material are linked, a discovery that could enable fundamental research as well as potential applications in spintronics. Credit: Myung-Geun Han and Yimei Zhu

Information in computers is transmitted through semiconductors by the movement of electrons and stored in the direction of electron spin in magnetic materials. To shrink devices while improving their performance – a goal of an emerging field called spin electronics (“spintronics”) – researchers are looking for unique materials that combine both quantum properties. Writing in Nature Materials, a team of chemists and physicists from Columbia discover a close link between electron transport and magnetism in a material called chromium sulfide bromide (CrSBr).

Created in the laboratory of chemist Xavier Roy, CrSBr is a so-called van der Waals crystal that can be peeled into stackable 2D layers a few atoms thick. Unlike related materials which are rapidly destroyed by oxygen and water, CrSBr crystals are stable under ambient conditions. These crystals also retain their magnetic properties at the relatively high temperature of -280F, obviating the need for expensive liquid helium cooled to a temperature of -450F,

“CrSBr is infinitely easier to use than other 2D magnets, allowing us to fabricate new devices and test their properties,” said Evan Telford, a postdoc at the Roy lab who earned a PhD in physics from Columbia in 2020. Last year, colleagues Nathan Wilson and Xiaodong Xu from the University of Washington and Xiaoyang Zhu from Columbia found a link between magnetism and the way CrSBr reacts to light. In current work, Telford has led the effort to explore its electronic properties.

The team used an electric field to study CrSBr layers through different electron densities, magnetic fields and temperatures – different parameters that can be tuned to produce different effects in a material. As the electronic properties of CrSBr changed, its magnetism also changed.

“Semiconductors have tunable electronic properties. Magnets have tunable spin configurations. In CrSBr, these two knobs are combined,” Roy said. “This makes CrSBr attractive both for basic research and for potential application in spintronics.”

Magnetism is a difficult property to measure directly, especially as the material shrinks in size, Telford explained, but it’s easy to measure how electrons move with a parameter called resistance. In CrSBr, resistance can serve as a proxy for otherwise unobservable magnetic states. “It’s very powerful,” Roy said, especially as researchers envision one day building chips out of such 2D magnets, which could be used for quantum computing and for storing huge amounts of data in a small space.

The link between the material’s electronic and magnetic properties was due to flaws in the layers – for the team, a fluke, Telford said. “People generally want the ‘cleanest’ material possible. Our crystals had flaws, but without them we wouldn’t have observed this coupling,” he said.

From there, the Roy lab is experimenting with ways to grow peelable van der Waals crystals with deliberate flaws, to improve the ability to fine-tune the properties of the material. They are also investigating whether different combinations of elements could work at higher temperatures while retaining these valuable combined properties.

Visualization of the atomic structure and magnetism of 2D magnetic insulators

More information:
Evan J. Telford et al, Coupling Between Magnetic Order and Charge Transport in a Two-Dimensional Magnetic Semiconductor, Natural materials (2022). DOI: 10.1038/s41563-022-01245-x

Provided by Columbia University Quantum Initiative

Quote: Unique Quantum Material Could Enable Ultra-Powerful Compact Computers (2022, May 20) Retrieved May 21, 2022 from https://phys.org/news/2022-05-unique-quantum-material-enable-ultra-powerful .html

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