Pseudopotential and structural effects on electronic properties in transition metal oxides using Wannier functions

How do pseudopotential choices affect the electronic transport properties in first-principles calculations? How does the atomic structure affect the computed properties? In this work, we present a comparison of six different pseudopotential libraries and their impact on computed material properties, including band gap, high-frequency permittivity, and electrical conductivity, using a set of transition metal oxides. We also highlight that Wannier functions can be used to calculate electronic transport properties of materials. Our workflow demonstrates that Wannier functions provide a reliable, accurate method to handle complex systems using any pseudopotential library. We validate and compare our results with existing theoretical works and experimental values from the literature. We find that the effect of various pseudopotentials on the calculated band gap, electrical conductivity, and high-frequency permittivity is negligible. Therefore, Wannier functions can be used to benchmark calculations of band gaps and electrical conductivities of metallic and semiconducting, as well as magnetic TMOs. We also find that the effect of the choice of the atomic structure (i.e., experimental vs. relaxed/optimized) on the electrical conductivity is not negligible. The experimental structure generally gives a more accurate result in comparison with experimental values of intrinsic conductivity than the relaxed atomic structure.