2013/08/06 by Manfred Bucher, Bucher, Manfred
Physics and Astronomy · Materials Science · #Physics of Superconductivity and Magnetism #Magnetic and transport properties of perovskites and related materials #Advanced Condensed Matter Physics
paper · pdf · doi:10.48550/arxiv.1308.1396
In line with the Coulomb-oscillator model of superconductivity, loop currents of excited 3s electrons from O2- ions, passing in the CuO2 plane through nuclei of nearest-neighbor oxygen quartets, create the antiferromagnetic phase of undoped copper oxides. Holes, introduced by alkaline-earth doping of La2CuO4, destroy the loop currents, thereby weakening antiferromagnetism until it disappears at doping x = 0.02. Further doping of La2-xAexCuO4 gives rise to incommensurate free-hole density waves whose wavelength is determined by the spacing of a doping superlattice. Modulating the ordering of the ions' magnetic moments, the charge-density wave, of incommensurability 2 delta, causes a magnetic density wave of incommensurability delta. The formula derived for delta(x) is in excellent agreement with data from X-ray diffraction and neutron scattering.