Atoms and molecules in crystalline solids are arranged in regular three-dimensional lattices. The atoms interact with each other via various forces, finally reaching a state of minimum energy. Near absolute zero, the lattice oscillations freeze, so that interactions between electron spins dominate. A particularly interesting case occurs when the spins cannot all align at the same time to reach a state of lowest energy. This results in a frustrated system in which the spins are almost completely disordered and are therefore referred to as a spin liquid.
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