Computational detective work by physicists has confirmed cerium zirconium pyrochlore is a 3D quantum spin liquid, a solid material in which quantum entanglement and the geometric arrangement of atoms cause electrons to fluctuate between quantum magnetic states no matter how cold they become.
Despite the name, quantum spin liquids are solid materials in which quantum entanglement and the geometric arrangement of atoms frustrate the natural tendency of electrons to magnetically order themselves in relation to one another. The geometric frustration in a quantum spin liquid is so severe that electrons fluctuate between quantum magnetic states no matter how cold they become.
Theoretical physicists routinely work with quantum mechanical models that manifest quantum spin liquids, but finding convincing evidence that they exist in actual physical materials has been a decadeslong challenge.
The inherent property of electrons that leads to magnetism is spin. Each electron behaves like a tiny bar magnet with a north and south pole, and when measured, individual electron spins always point up or down. In most everyday materials, spins point up or down at random. But electrons are antisocial by nature, and this can cause them to arrange their spins in relation to their neighbors in some circumstances. In magnets, for example, spins are collectively arranged in the same direction, and in antiferromagnets they are arranged in an up-down, up-down pattern.
At very low temperatures, quantum effects become more prominent, and this causes electrons to arrange their spins collectively in most materials, even those where spins would point in random directions at room temperature. Quantum spin liquids are a counterexample where spins do not point in a definite direction — even up or down — no matter how cold the material becomes.
The work has been published in npj Quantum Materials.