Theory for electron- and hole-doped cuprate superconductors: d-wave symmetry order parameter

¹ Institüt für Theoretische Physik, Freie Universität Berlin - D-14195 Berlin, Germany
² Physics Department, Kazan State University - 420008 Kazan, Russia

Received: 21 August 2000
Accepted: 4 December 2000

Abstract

Using as a model the Hubbard Hamiltonian, we determine various basic properties of electron- and hole-doped cuprate superconductors for a spin-fluctuation-induced pairing mechanism. We find for both hole- and electron-doped cuprates symmetry for the superconducting order parameter. We find a narrow doping range of superconductivity for electron-doped superconductors like and . The superconducting transition temperatures for various electron doping concentrations x are calculated to be much smaller than for hole-doped cuprates due to the different energy dispersion and a flat band well below the Fermi level for electron-doped superconductors. Lattice disorder may sensitively distort the symmetry via electron-phonon interaction. We present a general discussion of the symmetry of the order parameter which should apply also to other spin-fluctuation-induced superconductors. Furthermore, we show how our theory may also explain the neutron scattering data.