Optical and excitonic properties of transition metal oxide perovskites by the Bethe-Salpeter equation

Abstract

We present a systematic investigation of the role and importance of excitonic effects on the optical properties of transitions metal oxide perovskites. A representative set of fourteen compounds has been selected, including 3d (SrTiO3, LaScO3, LaTiO3, LaVO3, LaCrO3, LaMnO3, LaFeO3 and SrMnO3), 4d (SrZrO3, SrTcO3 and Ca2RuO4) and 5d (SrHfO3, KTaO3 and NaOsO3) perovskites, covering a band gap ranging from 0.1 eV to 6.1 eV and exhibiting different electronic, structural and magnetic properties. Optical conductivities and optical transitions including electron-hole interactions are calculated through the solution of the Bethe-Salpeter equation (BSE) with quasi-particle energies evaluated by single-shot G0W0 approximation. The exciton binding energies are computed by means of a model-BSE (mBSE), carefully benchmarked against the full BSE method, in order to obtain well-converged results in terms of k-point sampling. The predicted results are compared with available measured data, with an overall satisfactory agreement between theory and experiment.