Superconductivity and Magnetic Patterns

One of the most striking features of high-temperaturesuperconducting materials is an alternating up-and-down pattern ofelectron spins in an arrangement called antiferro magnetism. Scientists believe the ordered electron spins may be a sort of precursor to a material's superconductivity, since a material in this state that loses only a few electrons will become superconducting. In numerical studies of the Hubbard Model of interacting electrons, UC Davis theoretical physicist Richard Scalettar and his colleagues have found that this unusual magnetic pattern occurs when each atom has one electron, no more and no less, a finding which closely resembles experimentalists' observations. Exploring the magnetic behavior of electrons may help scientists better understand superconducting properties. "People are speculating that the electrons are interacting with the remnant of this magnetic pattern, and that's what makes new materials go superconducting," Scalettar says. In his Tuesday morning talk, Aug. 27, Scaletter will also review optical properties in both the Hubbard and Holstein models.

Media Resources

Andy Fell, Research news (emphasis: biological and physical sciences, and engineering), 530-752-4533,