title: Mechanistic insights on the electronic properties and electronic/atomic structure aspects in orthorhombic SrVO3thin films: XANES-EXAFS study.
abstract: Correlations among the B-O6 octahedra distortions, existing polymorphous phases, band structures and electronic conductivities of ABO3perovskites are matters for debate and require a deep understanding of their local atomic/electronic structures and diverse assets. In this study, to illustrate the distortion in V-O6 octahedra and its implication on the band structure and electronic properties, spectroscopic investigations on the RF-sputtering grown insulating SrVO3thin films were employed using X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). V K-edge and V L3,2-edge XANES, along with atomic multiplet calculations, have confirmed the 4+ oxidation state of V ions in the pristine and annealed SrVO3thin films. Lower t2g/egpeak intensity ratio and smaller energy separation between t2gand egpeaks in the O K-edge XANES spectra, compared to the VO2reference sample, have confirmed a larger V-O6 distortion in the orthorhombic SrVO3thin films. Moreover, from the EXAFS data analysis, the local orthorhombic structure has been identified in the pristine and annealed SrVO3thin films, compelling significant distortion in the V-O6 octahedra. Dimerization in the vanadium chains and V-V twisting, caused by V-O6 octahedra distortion, manifests a miscellaneous ligand field interaction between O 2p and V 3d orbitals and facilitates (i) a larger separation between the bonding and antibonding d‖orbitals and (ii) an upward shift of the π* band in the band structure, leading to larger band gaps in the insulating SrVO3thin films. Our spectroscopy results may open up new avenues for the mechanism of insulating/conducting character in other complicated perovskite materials using XANES-EXAFS.
authors.affiliation: Advance Analysis Centre, Korea Institute of Science and Technology (KIST), Seoul - 02792, Seoul, South Korea. sowon@kist.re.kr khchae@kist.re.kr.
authors.forename: Aditya
authors.identifier: http://orcid.org/0000-0003-4463-5238
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Advance Analysis Centre, Korea Institute of Science and Technology (KIST), Seoul - 02792, Seoul, South Korea. sowon@kist.re.kr khchae@kist.re.kr.
authors.forename: Mayora
authors.initials: M
authors.lastname: Varshney
authors.affiliation: Advance Analysis Centre, Korea Institute of Science and Technology (KIST), Seoul - 02792, Seoul, South Korea. sowon@kist.re.kr khchae@kist.re.kr.
authors.forename: Weon
authors.initials: W
authors.lastname: Cheol Lim
authors.affiliation: Pohang Accelerator Laboratory (POSTECH), Pohang - 37673, South Korea.
authors.forename: Hyun-Joon
authors.initials: HJ
authors.lastname: Shin
authors.affiliation: Advance Analysis Centre, Korea Institute of Science and Technology (KIST), Seoul - 02792, Seoul, South Korea. sowon@kist.re.kr khchae@kist.re.kr.
authors.forename: Jitendra
authors.initials: J
authors.lastname: Pal Singh
authors.affiliation: Advance Analysis Centre, Korea Institute of Science and Technology (KIST), Seoul - 02792, Seoul, South Korea. sowon@kist.re.kr khchae@kist.re.kr.
authors.forename: Sung
authors.initials: S
authors.lastname: Ok Won
authors.affiliation: Advance Analysis Centre, Korea Institute of Science and Technology (KIST), Seoul - 02792, Seoul, South Korea. sowon@kist.re.kr khchae@kist.re.kr.
authors.forename: Keun
authors.initials: K
authors.lastname: Hwa Chae