2001/08/08 by Guang-Ming Zhang, Shun-Qing Shen · 1 citation
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/physrevlett.87.157201
published as Physical Review Letters 87, 157201 (2001) · four pages in Revtex, no figures, accepted for publication in Physical Review Letters
arxiv created 2001/08/08 · openalex publication_date 2001/09/01 · arxiv updated 2013/01/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider a superexchange Hamiltonian, H\phantom\rule0ex0ex=\phantom\rule0ex0ex\ensuremath-\ensuremathΣ〈i,j〉(2Si\ifmmode \else \.\fiSj\ensuremath-(1)/(2))(2Ti\ifmmode \else \.\fiTj\ensuremath-(1)/(2)), which describes systems with orbital degeneracy and strong electron-phonon coupling in the limit of large on-site repulsion. In an SU(4) Schwinger boson representation, a reduced spin-orbital interaction is derived exactly, and a mean field theory has been developed. In one dimension, a spin-orbital liquid state with a finite gap is obtained. On a two-dimensional square lattice a novel type of spin-orbital ferromagnetically ordered state appears, while spin and orbital are antiferromagnetic. An important relation has been found, relating the spin and orbital correlation functions to the combined spin-orbital ones.