Mixed Mott-Hubbard and charge transfer nature of 4H-SrMnO3thin film on Si (100)

Arup Kumar Mandal; Anupam Jana; Sourav Chowdhury; Achyut Tiwari; R J Choudhary; D M Phase

doi:10.1088/1361-648X/abe8a3

Mixed Mott-Hubbard and charge transfer nature of 4H-SrMnO₃thin film on Si (100)

J Phys Condens Matter. 2021 May 10;33(23). doi: 10.1088/1361-648X/abe8a3.

Authors

Arup Kumar Mandal¹, Anupam Jana¹, Sourav Chowdhury¹, Achyut Tiwari², R J Choudhary¹, D M Phase¹

Affiliations

¹ UGC-DAE Consortium for Scientific Research, Indore-452001, Madhya Pradesh, India.
² Indian Institute of Technology (Indian School of Mines), Dhanbad-826004, Jharkhand, India.

PMID: 33973533
DOI: 10.1088/1361-648X/abe8a3

Abstract

Room temperature electronic structure of polycrystalline 4H-SrMnO₃thin 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 3dⁿLfinal state along with the 3d^n-1final state at the valence band edge of 4H-SrMnO₃thin film confirms that the ground state is strongly mixed between Mn 3dand O 2pstates. The estimated equivalent values of on-site Coulomb interaction energy (U) and O 2pto Mn 3d- charge transfer energy (Δ) (U≈ 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-SrMnO₃film. Despite having similar Mn 4+ valence state in 4H-SrMnO₃and cubic SrMnO₃, 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 MnO₆octahedra environment.

Keywords: SrMnO3 thin film; resonant photoemission spectroscopy; x-ray absorption spectroscopy.