In the paper "Field-tunable quantum disordered ground state in the triangular-lattice antiferromagnet NaYbO2," published in the journal Nature Physics, Wilson and colleagues Leon Balents, of the campus's Kavli Institute for Theoretical Physics, and Mark Sherwin, a professor in the Department of Physics, describe their discovery of a long-sought "quantum spin liquid state" in the material NaYbO2 (sodium ytterbium oxide). The study was led by materials student Mitchell Bordelon and also involved physics students Chunxiao Liu, Marzieh Kavand and Yuanqi Lyu, and undergraduate chemistry student Lorenzo Posthuma, as well as collaborators at Boston College and at the U.S. National Institute of Standards and Technology.
At the atomic level, electrons in one material's lattice structure behave differently, both individually and collectively, from those in another material. Specifically, the "spin," or the electron's intrinsic magnetic moment (akin to an innate bar magnet) and its tendency to communicate and coordinate with the magnetic moments of nearby electrons differs by material. Various types of spin systems and collective patterns of ordering of these moments are known to occur, and materials scientists are ever seeking new ones, including those that have been hypothesized but not yet shown to exist.
Moments - Degree - Certainty - Spin - Direction
"There are certain, more classical moments that let you know to a very high degree of certainty that the spin is pointing in a particular direction," Wilson explained. "In those, the quantum effects are small. But there are certain moments where the quantum effects are large, and you can't precisely orient the spin, so there is uncertainty, which we call 'quantum fluctuation.'"
Quantum magnetic states are those in which the magnetism of a material is primarily driven by such quantum fluctuations, generally derived from the uncertainty principle, intrinsic to magnetic moments. "So, you envision a magnetic moment, but the uncertainty principle says that I can't perfectly orient that in any...
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