Quantum materials display exotic behaviors due to the effects of quantum mechanics, or how matter acts on the very small scale of atoms and subatomic particles. The technologically relevant properties of quantum materials result from complex interactions of electron charge, orbital, and spin and their coupling to the material's crystal structure. For example, in some materials, electrons can flow freely without any resistance; this phenomenon, called superconductivity, could be harnessed to transmit power more efficiently. Typically, these properties emerge at low temperature, where crystals display low (broken) structural symmetry.
"Not surprisingly, this low-temperature regime is well studied," said Emil Bozin, a physicist in the X-ray Scattering Group of the Condensed Matter Physics and Materials Science (CMPMS) Division at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory. "Meanwhile, the high-temperature regime remains largely unexplored because it's associated with relatively high symmetry, which is considered uninteresting."
But Bozin and colleagues have recently discovered states of local symmetry breaking at high temperature. These local states are associated with electronic orbitals (regions within an atom where electrons are most likely to be found) that serve as orbital degeneracy lifting (ODL) "precursors" to what happens at low temperature. Orbital degeneracy refers to when orbitals have the same energy. Lifting of this degeneracy means that some orbitals will have a relatively higher energy and others a lower energy.
"We think such local states are in some way enablers of the material properties of interest that materialize at much-lower temperature," explained Bozin.
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