MODELING OF ZnO ELECTRONIC STRUCTURE FROM FIRST PRINCIPLES BY APPLYING ADVANCED FUNCTIONALS

Abstract

Subject of Research. We have studied the electronic structure of wurzite zinc oxide (ZnO) by quantum mechanical modeling using density functional theory (DFT) approach with different exchange-correlation energy functionals. Methods. The calculations were performed by means of generalized gradient approximation (GGA), Hubbard corrected generalized gradient approximation (DFT+U method) and hybrid functional PBE0. Main Results. The calculations have demonstrated that the basic GGA approach renders ZnO electronic structure with essential disadvantages demonstrating overestimated hybridization of zinc 3d and oxygen 2p shells and significantly underestimated bandgap. The inaccuracy for the latter has been eliminated by using the PBE0 approach, which is highly computationally demanding and increases the complexity of the calculations. We have shown that the best results complying with the experiment are obtained by applying Hubbard correction to all atoms of unit cell. Practical Relevance. The study shows the necessity of Hubbard correction usage when calculating zinc oxide electronic structure with the parameter of on-site repulsion “U” applied to both Zn and O atoms. The physical aspects and details of all used approaches and their computational demands are discussed.