Ab Initio Study of the Electronic Structure and Lattice Dynamics of Scheelite Type AgTcO4

To build a safe, sustainable, and reliable disposal system for radioactive waste from the nuclear industry, researchers need to understand the physical and chemical aspects of technetium (Tc)-based oxides. Here, structure-property correlation studies of scheelite-type AgTcO4 are performed using ab initio calculations. The full phonon dispersion studies reveal the dynamical stability of this compound. The partial phonon density of states, including the complete mode assignment of the vibrational frequencies, shows the maximum involvement of silver (Ag) atoms in the low-frequency range, while high contribution of oxygen atoms and average contribution from Tc atoms are found throughout the frequency region. The electronic band structure shows that the main contribution to the bottom of the conduction band is Tc d states with a minor contribution from oxygen p states, while the top of the valence band is from Ag d states, which are responsible for the electronic transitions. The frequency-dependent dielectric functions and computed optical properties show near-isotropy behavior and, together with absorption peak in the low-energy range, indicate that AgTcO4 may be a good phosphor when doped with a suitable activator. The estimations are grounded by the available experimental data and also deliver direction for distinct and futuristic applications of AgTcO4.