NIST has confirmed long-standing suspicions among physicists that electrons in a crystalline structure called a kagome (kah-go-may) lattice can form a “spin liquid,” a novel quantum state of matter in which the electrons’ magnetic orientation remains in a constant state of change.
The research shows that a spin liquid state exists in Herbertsmithite—a mineral whose atoms form a kagome lattice, named for a simple weaving pattern of repeating triangles well-known in Japan. Kagome lattices are one of the simplest structures believed to possess a spin liquid state, and the new findings, revealed by neutron scattering, indeed show striking evidence for a fundamental prediction of spin liquid physics.
This image depicts magnetic effects within Herbertsmithite crystals, where green regions represent higher scattering of neutrons from NIST’s Multi-Angle Crystal Spectrometer (MACS). Scans of typical highly-ordered magnetic materials show only isolated spots of green, while disordered materials show uniform color over the entire sample. The in-between nature of this data shows some order within the disorder, implying the unusual magnetic effects within a spin liquid.
The apparent simplicity of Herbertsmithite belies the complexity of the spin liquid state that it apparently supports, Broholm says, which could make it useful someday.
“The structural simplicity of Herbertsmithite is valuable if we are to put the quantum spin liquid to use—as proposed for information processing, for example,” he says. “Complex chemistry usually brings disorder, but this material is relatively simple, so it realizes the quantum spin liquid with higher fidelity.”
SOURCE – NIST