Magnetic Interaction in Doped 2D Perovskite Cuprates with Nanoscale Inhomogeneity: Lattice Nonlocal Effects vs. Superexchange

Lattice and superexchange effects in doped CMRmanganites

We report on the influence of the lattice degrees of freedom on charge, orbital and spin correlations in colossal magnetoresistance (CMR) manganites. For the weakly doped compounds we demonstrate that the electron-phonon coupling promotes the trapping of charge carriers, the disappearance of the orbital polaron pattern and the breakdown of ferromagnetism at the CMR transition. The role of diffe...

Magnetic Interaction in Insulating Cuprates

We examine two-spin (2S) and cyclic four-spin (4S) magnetic interactions in insulating ladder and two-dimensional (2D) cuprates. By a comparison of eigenstates between d-p and Heisenberg models, we evaluate magnitudes of these interactions. We find that the 4S interaction is ∼10 % of nearest neighboring 2S interaction, and a diagonal 2S interaction is considerably small. The 4S interaction for ...

Theory of anisotropic superexchange in insulating cuprates.

Spin-orbit corrections to superexchange are calculated using the method of Moriya [T. Moriya, Phys. Rev. 120 91, (1960)] for two of the insulating parent compounds of the cuprate superconductors: (1) La2−xNdxCuO4 where the CuO6 octahedra forming each Cu-O layer are tilted in staggered fashion about an axis which depends on x and temperature; and (2) YBa2Cu3O6+x (x ∼ 0.4) where the Cu-O layers f...

Magnetic Ordering in Gd Monopnictides: Indirect Exchange Versus Superexchange Interaction

Fermi Arcs vs. Fermi Pockets in Electron-doped Perovskite Iridates

We report on an angle resolved photoemission (ARPES) study of bulk electron-doped perovskite iridate, (Sr(1-x)La(x))3Ir2O7. Fermi surface pockets are observed with a total electron count in keeping with that expected from La substitution. Depending on the energy and polarization of the incident photons, these pockets show up in the form of disconnected "Fermi arcs", reminiscent of those reporte...