Electronic structure and energy gaps evaluation of perovskite manganite single crystals using XES and XAS spectroscopy

Abstract

In this work, the X-ray absorption spectroscopy (XAS), and emission spectra spectroscopy (XES) carried out in synchrotron radiation, were employed to evaluate the electronic structure, and bandgap energy of perovskite manganese: LaSr2Mn2O7, La1.2(Ba, Ca)1.8Mn2O7 and La0.95Ba0.05MnO3 single crystals. Atomic multiple calculations also have been utilized to assess the Jahn-Teller distortion and extracting quantitative details on the ligand metal charge transfer (LMCT). We find that Mn ions possess mixed oxidation states Mn3+/Mn4+ as dominated ground configurations with a small fraction of Mn2+. The trivalent Mn3+ (Mn2O3) exist with high spin (HS) 2p3d4 (e g3 t2 g1). The band edge positions and bandgap energy are remarkably influenced by Alkaline (Ba/Ca) dopant ions as well as by temperature, where, the low temperature causes the bandgap to be significantly narrowing and that has been stated and discussed.