Abstract
The local density approximation (LDA) and generalized gradient approximations (GGA) of density functional theory systematically overestimate the electronic polarizability of materials. We calculate the dielectric constant of NiO by the direct method and find, contrary to previous suggestions, that the method reduces the polarization such that decreases monotonically with increasing . We illustrate the existence of a linear term in the effective exchange-correlation potential that counteracts the external electric field, thus demonstrating that the decrease of is intrinsic to the correction. The reduction of the polarization is due mostly to reduced orbital mixing between the unoccupied states and the occupied states. Our work establishes as a viable method for calculating the dielectric constants of correlated materials.
- Received 3 October 2012
DOI:https://doi.org/10.1103/PhysRevB.87.075115
©2013 American Physical Society