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

Lorenzo Varrassi; Peitao Liu; Zeynep Ergönenc Yavas; Menno Bokdam; Georg Kresse; Cesare Franchini

paper

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

arXiv:2106.14632

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 3 $d$ (SrTiO $_{3}$ , LaScO $_{3}$ , LaTiO $_{3}$ , LaVO $_{3}$ , LaCrO $_{3}$ , LaMnO $_{3}$ , LaFeO $_{3}$ and SrMnO $_{3}$ ), 4 $d$ (SrZrO $_{3}$ , SrTcO $_{3}$ and Ca $_{2}$ RuO $_{4}$ ) and 5 $d$ (SrHfO $_{3}$ , KTaO $_{3}$ and NaOsO $_{3}$ ) 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 $G_{0} W_{0}$ 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.