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Title: Epitaxial growth and electronic structure of oxyhydride SrVO{sub 2}H thin films

Abstract

Oxyhydride SrVO{sub 2}H epitaxial thin films were fabricated on SrTiO{sub 3} substrates via topotactic hydridation of oxide SrVO{sub 3} films using CaH{sub 2}. Structural and composition analyses suggested that the SrVO{sub 2}H film possessed one-dimensionally ordered V-H{sup −}-V bonds along the out-of-plane direction. The synthesis temperature could be lowered by reducing the film thickness, and the SrVO{sub 2}H film was reversible to SrVO{sub 3} by oxidation through annealing in air. Photoemission and X-ray absorption spectroscopy measurements revealed the V{sup 3+} valence state in the SrVO{sub 2}H film, indicating that the hydrogen existed as hydride. Furthermore, the electronic density of states was highly suppressed at the Fermi energy, consistent with the prediction that tetragonal distortion induces metal to insulation transition.

Authors:
; ; ;  [1];  [2]; ;  [3];  [4];  [1];  [5]
  1. Department of Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  2. Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa 213-0012 (Japan)
  3. Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan)
  4. Japan Synchrotron Radiation Research Institute (JASRI)/SPring-8, Mikazuki-cho, Hyogo 679-5198 (Japan)
  5. (Japan)
Publication Date:
OSTI Identifier:
22598887
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; ABSORPTION SPECTROSCOPY; AIR; ANNEALING; CALCIUM HYDRIDES; DENSITY OF STATES; ELECTRONIC STRUCTURE; EPITAXY; HYDROGEN; ONE-DIMENSIONAL CALCULATIONS; OXIDES; PHOTOEMISSION; STRONTIUM TITANATES; SUBSTRATES; THICKNESS; THIN FILMS; VANADIUM IONS; X-RAY SPECTROSCOPY

Citation Formats

Katayama, Tsukasa, Chikamatsu, Akira, E-mail: chikamatsu@chem.s.u-tokyo.ac.jp, Yamada, Keisuke, Onozuka, Tomoya, Shigematsu, Kei, Minohara, Makoto, Kumigashira, Hiroshi, Ikenaga, Eiji, Hasegawa, Tetsuya, and Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa 213-0012. Epitaxial growth and electronic structure of oxyhydride SrVO{sub 2}H thin films. United States: N. p., 2016. Web. doi:10.1063/1.4961446.
Katayama, Tsukasa, Chikamatsu, Akira, E-mail: chikamatsu@chem.s.u-tokyo.ac.jp, Yamada, Keisuke, Onozuka, Tomoya, Shigematsu, Kei, Minohara, Makoto, Kumigashira, Hiroshi, Ikenaga, Eiji, Hasegawa, Tetsuya, & Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa 213-0012. Epitaxial growth and electronic structure of oxyhydride SrVO{sub 2}H thin films. United States. doi:10.1063/1.4961446.
Katayama, Tsukasa, Chikamatsu, Akira, E-mail: chikamatsu@chem.s.u-tokyo.ac.jp, Yamada, Keisuke, Onozuka, Tomoya, Shigematsu, Kei, Minohara, Makoto, Kumigashira, Hiroshi, Ikenaga, Eiji, Hasegawa, Tetsuya, and Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa 213-0012. 2016. "Epitaxial growth and electronic structure of oxyhydride SrVO{sub 2}H thin films". United States. doi:10.1063/1.4961446.
@article{osti_22598887,
title = {Epitaxial growth and electronic structure of oxyhydride SrVO{sub 2}H thin films},
author = {Katayama, Tsukasa and Chikamatsu, Akira, E-mail: chikamatsu@chem.s.u-tokyo.ac.jp and Yamada, Keisuke and Onozuka, Tomoya and Shigematsu, Kei and Minohara, Makoto and Kumigashira, Hiroshi and Ikenaga, Eiji and Hasegawa, Tetsuya and Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa 213-0012},
abstractNote = {Oxyhydride SrVO{sub 2}H epitaxial thin films were fabricated on SrTiO{sub 3} substrates via topotactic hydridation of oxide SrVO{sub 3} films using CaH{sub 2}. Structural and composition analyses suggested that the SrVO{sub 2}H film possessed one-dimensionally ordered V-H{sup −}-V bonds along the out-of-plane direction. The synthesis temperature could be lowered by reducing the film thickness, and the SrVO{sub 2}H film was reversible to SrVO{sub 3} by oxidation through annealing in air. Photoemission and X-ray absorption spectroscopy measurements revealed the V{sup 3+} valence state in the SrVO{sub 2}H film, indicating that the hydrogen existed as hydride. Furthermore, the electronic density of states was highly suppressed at the Fermi energy, consistent with the prediction that tetragonal distortion induces metal to insulation transition.},
doi = {10.1063/1.4961446},
journal = {Journal of Applied Physics},
number = 8,
volume = 120,
place = {United States},
year = 2016,
month = 8
}
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  • Stoichiometric SrVO{sub 3} thin films were grown over a range of cation fluxes on (001) (La{sub 0.3}Sr{sub 0.7})(Al{sub 0.65}Ta{sub 0.35})O{sub 3} substrates using hybrid molecular beam epitaxy, where a thermal effusion cell was employed to generate a Sr flux and V was supplied using the metal-organic precursor vanadium oxytriisopropoxide (VTIP). By systematically varying the VTIP flux while keeping the Sr flux constant, a range of flux ratios were discovered in which the structural and electronic properties of the SrVO{sub 3} films remained unaltered. The intrinsic film lattice parameter and residual resistivity were found to be the smallest inside the growthmore » window, indicating the lowest defect concentration of the films, and rapidly increased for cation flux ratios deviating from ideal growth condition. Reflection high-energy electron diffraction showed that films grown within this range had smooth surfaces and diffraction patterns were free of additional spots, while otherwise the growing surface was rough and contained additional crystalline phases. Results show the existence of a SrVO{sub 3} growth window at sufficiently high growth temperature, in which high-quality, stoichiometric films can be grown in a robust, highly reproducible manner that is invulnerable to unintentional flux variation.« less