Tuning the Plasma Frequency in Correlated Transition Metal Oxides

Transparent conductors, materials that bring together electrical conductivity with optical transparency, are usually designed starting with a wide transparent insulator, which is then doped to introduce charge carriers. However, this approach is often limited in the maximum conductivity that can be obtained because of both defect scattering and doping bottlenecks. An alternative approach is to design a metal that has weak interband absorption and a plasma frequency that is close to but below the lower end of the visible spectrum. In this talk, we present a systematic first principles study of the effect of biaxial strain, octahedral rotations, and layering on the transparent conducting properties of d1 perovskites. We employ Density Functional Theory in conjunction with Dynamical Mean Field Theory (DFT+DMFT) to predict the correlation induced suppression of the plasma frequency and show that it can be significant even in the 4d transition metal oxides. We show that factors such as polyhedral connectivity induce changes much more significant than strain or octahedral rotations in weakly correlated oxides.