Effect of La and Sc Doping on the Structural, Electronic, and Optical Properties of Cubic HfO2: A DFT-Based Spin-Polarized Calculation

The effect of lanthanum (La) and Scandium (Sc) doping on the structural, electronic, and optical properties of cubic hafnium oxide (c-HfO2) has been thoroughly investigated using density functional theory (DFT). The spin-polarized calculations have been performed using the MGGA-TB09 + c exchange–correlation functional. In this study, 6.25% of La and Sc are incorporated into the cubic hafnium oxide structure. When a hafnium (Hf) atom is replaced by a La and Sc atom in a pure cubic HfO2 crystal, a reduction in the band gap (Eg) is observed due to an increase of the valence band maxima. The complex dielectric function, extinction coefficient, refractive index, reflectivity, energy loss function, absorption coefficient, and optical conductivity for pure, La-doped, and Sc-doped cubic HfO2 have been calculated, and the results show a higher value of the dielectric constant for HfO2 after doping. The states close to the Fermi level are attributed to hafnium 5d states with a significant contribution from oxygen 2p states in the majority spin. Compared to previous computational studies, the MGGA-TB09 + c approach produces good results on all the parameters of its material properties.