Description of magnetic interactions in strongly correlated solids via range-separated hybrid functionals

The performance of two range-separated hybrid (HSE and $\text{LC-}\omega \text{PBE}$) exchange-correlation functionals for describing narrow-band magnetic solids and, more precisely, for predicting magnetic coupling constants has been investigated for a large set of systems for which accurate experimental data exist. The set includes superconducting cuprates parent compounds and transition-metal oxides and fluorides exhibiting a broad range of magnetic coupling values. Both HSE and $\text{LC-}\omega \text{PBE}$ provide an overall improvement over the description arising from standard hybrid functionals such as the well-known B3LYP. Nevertheless, the two range-separated hybrid functionals still overestimate antiferromagnetic and ferromagnetic interactions although significantly less than B3LYP. The increased accuracy of $\text{LC-}\omega \text{PBE}$ suggests that the approximations and exact constraints included in the definition of this long-range corrected hybrid functional have important consequences for the accurate description of exchange and correlation effects of the electronic structure of magnetic solids and other systems exhibiting localized spins.

Figure 1

(Color online) Schematic representation of the ${\text{Ni}}_2{\text{O}}_{10}$ and ${\text{Ni}}_2{\text{O}}_{11}$ moieties defining the first region of the embedded-cluster models, including the TIPs in the second region (small external dark spheres), used to extract the $J_1$ and $J_2$ magnetic coupling parameters in NiO.

Figure 2

(Color online) Plot of calculated vs experimental values of the magnetic coupling constants for the materials of interest in the present work. The dashed line corresponds to a perfect fit and is included as reference.