Exchange parameters from approximate self-interaction correction scheme

The approximate atomic self-interaction correction (ASIC) method to density functional theory is put to the test by calculating the exchange interaction for a number of prototypical materials, critical to local exchange and correlation functionals. ASIC total energy calculations are mapped onto a Heisenberg pairwise interaction and the exchange constants J are compared to those obtained with other methods. In general the ASIC scheme drastically improves the band structure, which for almost all the cases investigated resemble closely available photoemission data. In contrast the results for the exchange parameters are less satisfactory. Although ASIC performs reasonably well for systems where the magnetism originates from half-filled bands, it suffers from similar problems than those of local density approximation for other situations. In particular, the exchange constants are still overestimated. This reflects a subtle interplay between exchange and correlation energy, not captured by the ASIC.