Tuning electronic structure and optical properties of Ba0.875Yb0.125TiO3 via transition metal substitution: A DFT study

The electronic structure and optical properties (such as the dielectric function, refractive index, absorption, and reflectivity) of Cubic BaTiO 3 co-doped with Yb at site A and transition metal elements M ([Formula: see text], Ru, Zr, Pt, Pd) at site B were studied using the first-principles calculations based on density functional theory (DFT). It is suggested that the energy band gap width increases from 3.15[Formula: see text]eV for pure BaTiO 3 (BT) to 3.86[Formula: see text]eV for Ba[Formula: see text]Yb[Formula: see text]Ti[Formula: see text]Zr[Formula: see text]O 3 . Impurity levels near the Fermi level across the Fermi surface were introduced by B-site transition metals (such as Pd, Pt, Rh, Ru, Tc, and V) doping in Ba[Formula: see text]Yb[Formula: see text]TiO 3 . The doping system with 12.5% Pd, Pt, Rh, and Ru, respectively, doped at the B-site of Ba 7 YbTi 8 O[Formula: see text] exhibits enhanced reflectivity, reaching up to [Formula: see text]30% at specific visible wavelengths (e.g., 2.5[Formula: see text]eV), which represents an increase of 15–30 percentage points compared with pure BaTiO 3 over the 1.6–3.1[Formula: see text]eV range. The peak values of the refractive index are enhanced by 10–25%, and the corresponding photon energies are blueshifted by 0.3–1.2[Formula: see text]eV. Transition metal doping increases the static dielectric constant, with the largest value reaching 7.7867 for the Pt-doped system, a [Formula: see text]27% increase over the pure phase (6.13).