The effect of removal of self-interaction error on the magnetic exchange couplings*

Spin coupling within and between molecules has played an important role in the design and development of molecular magnets, spintronics, and memory devices. Accurate theoretical determination of magnetic properties in molecular complexes has therefore become crucial. The Green's function (GF)-based approach, often used in solid-state physics, for computing exchange coupling can potentially offer additionals insights into local pathway in exchange spin coupling. We implement this approach into the UTEP-NRLMOL and FLOSIC codes and apply it, along with Noodleman’s spin-projected (SP) broken-symmetry approach, to study the exchange coupling in a set of molecules. In particular, we use Fermi-Lowdin self-interaction method to investigate the role of self-interaction error in predicting exchange-coupling with three (LSDA, PBE, and SCAN) non-empirical density functional approximations that correspond to the first three rungs of Perdew-Schmidt ladder of functionals.