• Chowdhury, Sourav
• Tiwari, Achyut
• Mandal, Arup Kumar
• Jana, Anupam
• Phase, D. M.

Abstract

<jats:title>Abstract</jats:title><jats:p>Room temperature electronic structure of polycrystalline 4H–SrMnO<jats:sub>3</jats:sub> thin film grown on Si (100) substrate has been studied using resonance photo emission spectroscopy and soft x-ray absorption spectroscopy measurements. Presence of charge transfer screen Mn 3<jats:italic>d</jats:italic><jats:sup><jats:italic>n</jats:italic></jats:sup><jats:italic><jats:underline>L</jats:underline></jats:italic> final state along with the 3<jats:italic>d</jats:italic><jats:sup>n-1</jats:sup> final state at the valence band edge of 4H–SrMnO<jats:sub>3</jats:sub> thin film confirms that the ground state is strongly mixed between Mn 3<jats:italic>d</jats:italic> and O 2<jats:italic>p</jats:italic> states. The estimated equivalent values of on-site Coulomb interaction energy (<jats:italic>U</jats:italic>) and O 2<jats:italic>p</jats:italic> to Mn 3<jats:italic>d</jats:italic>- charge transfer energy (Δ) (<jats:italic>U</jats:italic> ≈ Δ ≈ 4.8 eV) from the combination of occupied and unoccupied spectra further confirm the intermediate Mott–Hubbard and charge transfer insulator nature of 4H–SrMnO<jats:sub>3</jats:sub> film. Despite having similar Mn 4+ valence state in 4H–SrMnO<jats:sub>3</jats:sub> and cubic SrMnO<jats:sub>3</jats:sub>, 4H phase is observed to reveal much higher band gap ∼1.5 eV than the cubic phase (0.3 eV), which arises due to different MnO<jats:sub>6</jats:sub> octahedra environment.</jats:p>

Topics

• impedance spectroscopy
• phase
• thin film
• x-ray absorption spectroscopy