A review on DFT + U scheme for structural, electronic, optical and magnetic properties of copper doped ZnO wurtzite structure

Abstract

Some efforts have been made on Cu-doped ZnO (CZO) structures to study the electronic, structural, magnetic and optical properties from first-principles calculations by different computer codes. This is very interesting to review in detail about CZO structures. A summary of the convergence criteria of geometry optimization for CZO structures from the literature survey (2010–2021) is tabulated and discussed. The impact of the Hubbard-U scheme in the exchange-correlation functional on the standard Density Functional Theory (DFT) miscalculation for CZO properties is comprehensively reviewed. The inclusion of Ud-Zn, Ud-Cu and Up-O all to gather leads to a correct energy band gap, and exhibits a slight effect on the lattice constant. The values of Ud-Zn, Ud-Cu and Up-O have a considerable impact on the intensity and position of the main peaks of the imaginary part. The magnetic phase of the CZO structure is found to be influenced by both Ud,Zn and Ud,Cu. More attention is paid to the influence of Cu doping content on CZO properties, including electronic, structural, optical and magnetic properties. The magnetic moment mainly comes from Cu ions with little contribution from O ions. Ferromagnetic (FM) spin ordering of Cu ions are suggested to be mediated by the holes induced in p-d hybridization. Finally, some perspectives for future studies are discussed as well.