Apr 7 2020
Physicists at the University of Arkansas have made a recent discovery, which could be helpful to scientists in determining the existence of quantum spin liquids—a new state of matter.
Image Credit: University of Arkansas.
Since they were first hypothesized in the 1970s, quantum spin liquids have been enigmatic. If the existence of quantum spin liquids is established, it could open a path toward considerably faster, next-generation quantum computing.
The focus and research of scientists have been on what is called the Kitaev-type of spin liquid, which has been named after Alexei Kitaev, a Russian scientist who was the first to propose its existence. Specifically, they have widely investigated two materials—RuCl3 and Na2IrO—as candidates for this type of materials. Both of these materials exhibit small quantum spin numbers.
Traditional candidates are pretty limited to only these two.
Changsong Xu, Researcher, Department of Physics, University of Arkansas
Xu is the first author of the study that was published recently in the Physical Review Letters journal.
As part of the latest study, the physicists from the University of Arkansas have considerably increased the number of materials that could be possible candidates as Kitaev quantum spin liquids by analyzing materials that have higher quantum spin numbers, as well as by applying physical strain to the materials to tune their magnetic states.
Suddenly, we realize there are dozens of candidates we can propose.
Changsong Xu, Researcher, Department of Physics, University of Arkansas
Quantum spin liquids are characterized by their strange magnetic arrangement. Magnets have a north and south pole, which are collectively known as dipoles. These are typically generated by the quantum spin of electrons. Within a magnetic material, all the dipoles tend to be parallel to one another (ferromagnetism) or periodically alternate their up and down direction (antiferromagnetism).
The dipoles are not so well ordered when it comes to the hypothetical quantum spin liquids. By contrast, they display strange ordering within a short distance from each other. Different kinds of spin liquids are produced by different types of ordering.
Xu collaborated with Laurent Bellaiche, Distinguished Professor of Physics, and collaborators from China and Japan. They used computational models to assess a Kitaev quantum spin liquid state in materials like chromium iodide and chromium germanium telluride.
The study was funded by grants from the Arkansas Research Alliance and the Department of Energy. According to Xu, the research will offer scientists many more materials to investigate in their quest to establish the existence of quantum spin liquids.