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 (E-g) 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.