Abstract
Magnetic coupling in ionic solids is studied using a density functional theory, DFT, approach applied to suitable cluster models representing KNiF3, K2NiF4, and La2CuO4. A mapping between eigenstates of the exact nonrelativistic and spin model Hamiltonians allows us to obtain the magnetic coupling constant J and to compare the DFT values with either experiment or previous theoretical studies based on the use of accurate wave functions. In the present work different correlation and exchange functionals are explored. Numerical results show that it is possible to reach very good agreement with experiment. Surprisingly, it is shown that the difficulty of the local spin density approximation in describing the antiferromagnetic behavior of these compounds lies not in the correlation but in the exchange part of the density functional. Hybrid functionals, which include a component of the full, nonlocal, “exact” exchange interaction yield qualitatively and semiquantitatively correct magnetic interactions. The origin of this behavior is discussed from the point of view of the adiabatic connection formula.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
