Interplay of charge, spin, orbital and lattice correlations in colossal magnetoresistance manganites

摘要

We derive a realistic microscopic model for doped colossal magnetoresistance manganites, which includes the dynamics of charge, spin, orbital and lattice degrees of freedom on a quantum mechanical level. The model respects the SU(2) spin symmetry and the full multiplet structure of the manganese ions within the cubic lattice. Concentrating on the hole doped domain (0 ≤ x ≤ 0.5) we study the influence of the electron-lattice interaction on spin and orbital correlations by means of exact diagonalisation techniques. We find that the lattice can cause a considerable suppression of the coupling between spin and orbital correlations. In addition, our calculation gives detailed insights into orbital correlations and demonstrates the possibility of complex orbital states.