Systematic Study of the Effect of HSE Functional Internal Parameters on the Electronic Structure and Band Gap of a Representative Set of Metal Oxides

The effect of the amount of Hartree-Fock mixing parameter (a) and of the screening parameter (w) defining the range separated HSE type hybrid functional is systematically studied for a series of seven metal oxides: TiO2, ZrO2, CuO2, ZnO, MgO, SnO2, and SrTiO3. First, reliable band gap values were determined by comparing the optimal a reproducing the experiment with the inverse of the experimental dielectric constant. Then, the effect of the w in the HSE functional on the calculated band gap was explored in detail. Results evidence the existence of a virtually infinite number of combinations of the two parameters which are able to reproduce the experimental band gap, without a unique pair able to describe the full studied set of materials. Nevertheless, the results point out the possibility of describing the electronic structure of these materials through a functional including a screened HF exchange and an appropriate correlation contribution. (C) 2017 Wiley Periodicals, Inc.