Ab initio determination of the dielectric response of GaAs, AlAs, C, and SrO in the weighted-density approximation

We investigate the accuracy of the weighted-density approximation (WDA) in predicting the dielectric response of materials from first-principles. WDA is a genuinely non-local formulation for the exchange-correlation term of d ensity-functional theory. Still, it can be cast into a computationally trac table scheme, allowing for practical applications in pseudopotential calcul ations. We have selected a group of materials with increasingly ionic chara cter (C, GaAs, AlAs, and SrO), and we have calculated the static dielectric constant as a supercell limit of the electronic response to an applied ele ctric field at finite q. The WDA response is found to be somewhat lower tha n LDA, in agreement with the experimental trend. (C) 1999 Published by Else vier Science Ltd. All rights reserved.