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Dopant Structural Distortions In High-Temperature Superconductors: An Active Or A Passive Role?, Daniel Haskel, Edward A. Stern, Fatih Dogan, Arnie R. Moodenbaugh

Materials Science and Engineering Faculty Research & Creative Works

The parent compounds of high-temperature superconductors, such as YBa2Cu3O6 and La2CuO4, are strongly interacting electron systems, rendering them insulators with Mott-Hubbard gaps of a few electronvolts. Charge carriers (holes) are introduced by chemical doping, causing an insulator-metal (IM) transition and, at low temperatures, superconductivity. the role of dopants is widely seen as limited to the introduction of holes into the CuO2 planes (i.e. occupying electronic states derived from Cu and O 2px,y atomic orbitals). Most theories of high-Tc superconductivity deal with pairing interactions between these planar holes. Local distortions around dopants are poorly understood, because of the experimental difficulty in …