Photoemission spectroscopy study of metal-insulator transition in SrMn1-x Fex O3

Electronic structures of cubic perovskite oxides of SrMn1-x Fex O3 (0≤x≤1) have been investigated by employing photoemission spectroscopy (PES) and soft x-ray absorption spectroscopy (XAS). The spectral intensity near the Fermi level [I (EF)] is found to be finite in Fe3d PES of SrFeO3. I (EF) increases with x in Fe3d PES of SrMn1-x Fex O3, while it is negligibly small in Mn3d PES for all x. The O1s XAS for SrFeO3 also shows the finite spectral intensity near the Fermi level. These findings provide the experimental evidence for the metal-insulator transition in SrMn1-x Fex O3 with decreasing x and imply the importance of Fe3d electrons in determining the metallic states in SrMn1-x Fex O3. First principles band structure calculations for SrFeO3 and SrMnO3 support these findings in PES/XAS.