2009/12/14 by E. R. Ylvisaker, Rajiv R. P. Singh, R. R. P. Singh +2
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.81.180405
5 pages, 2 figures
arxiv created 2009/12/14 · openalex publication_date 2010/05/20 · arxiv updated 2013/05/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We examine magnon and orbiton behavior in localized O2 antibonding molecular \ensuremathπ^\ensuremath∗ orbitals using an effective Kugel-Khomskii Hamiltonian derived from a two-band Hubbard model with hopping parameters taken from ab initio density-functional calculations. The considerable difference between intraband and interband hoppings leads to a strong coupling between the spin-wave dispersion and the orbital ground state, providing a straightforward way of experimentally determining the orbital ground state from the measured magnon dispersion. The near degeneracy of different orbital ordered states leads to stacking defects which further modulate spin-fluctuation spectra. Proliferation of orbital domains disrupts long-range magnetic order, thus causing a significant reduction in the observed N'eel temperature.