Performance of scaled self-interaction correction to semilocal functionals

Most semilocal functionals suffer from self-interaction error (SIE). Perdew and Zunger (PZ)¹ applied self-interaction correction (SIC) to each delocalized Kohn-Sham orbital by subtracting the SIE from each occupied orbital. The Fermi-Lowdin orbital self-interaction correction (FLOSIC) uses size-extensive localized Fermi-Lowdin orbitals that improve the results for the properties like barrier heights that involves strong SIE, as in stretched bonds. However, it worsens the equilibrium properties such as atomization energies, as FLOSIC applied to a functional violates the exact constraints and the appropriate norms that the semilocal approximations satisfy². Here, we apply a scaled PZ SIC to LSDA, PBE, and SCAN and calculated different properties such as electron affinity, ionization potential, barrier height, atomization energy, and bond length of some representative test sets. We find that the scaled SIC works well for both the equilibrium properties and for the features that involve stretched bonds or noded densities.

1. J. P. Perdew and A. Zunger, Phys. Rev. B 23, 5048 (1981)
2. B. Santra and J. P. Perdew, J. Chem. Phys. 150, 174106 (2019)