Calculation of Magnetic Exchange Interactions in Mott-Hubbard Systems

An efficient method of computing magnetic exchange interactions in systems with strong correlations is introduced. It is based on a magnetic force theorem that evaluates linear response due to rotations of magnetic moments and uses a generalized spectral density functional framework allowing us to explore several approximations ranging from local density functional to exact diagonalization based dynamical mean field theory. Applications to spin waves and magnetic transition temperatures of $3d$ metal mono-oxides as well as high-$T_c$ superconductors are in good agreement with experiment.

Figure 1

Theoretical spin-wave dispersions for NiO (solid lines) calculated by LSDA, $\mathrm{LDA}+U$, Hubbard I and cluster exact diagonalization (CED) diagonalization impurity solvers in comparison with the experiment (circles) [35].