Electrical Properties of Epitaxial Thin Films of Oxyhydrides ATiO3鈥?i>xHx (A = Ba and Sr)

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• 作者：Guillaume Bouilly ; Takeshi Yajima ; Takahito Terashima ; Wataru Yoshimune ; Kousuke Nakano ; C茅dric Tassel ; Yoshiro Kususe ; Koji Fujita ; Katsuhisa Tanaka ; Takafumi Yamamoto ; Yoji Kobayashi ; Hiroshi Kageyama
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：September 22, 2015
• 年：2015
• 卷：27
• 期：18
• 页码：6354-6359
• 全文大小：294K
• ISSN：1520-5002

文摘

We have studied electronic properties of perovskite oxyhydrides ATiO_3鈥?i>xH_x (A = Ba, Sr). Epitaxial thin films of ATiO_3鈥?i>xH_x with various hydride compositions, up to x = 0.58 for Ba and x = 0.45 for Sr, are prepared by the low-temperature CaH₂ reduction of the corresponding oxide films deposited on (LaAlO₃)_0.3(SrAl_0.5Ta_0.5O₃)_0.7 (LSAT) substrates by pulsed laser deposition. Resistivity measurements for A = Sr show a metallic phase over a wide range of H^{鈥?/sup> composition, implying a substantial stabilization of H 1s orbitals that should be distributed over O 2p orbitals. On the other hand, for A = Ba, a semiconducting behavior is seen up to 鈭?鈥?% of H鈥?/sup> substitution. Interestingly, a similar contrasting behavior is observed in a Nb-substituted BaTiO₃ and SrTiO₃, which suggests that a local cation鈥搊ff centering in lightly doped Ba films creates in-gap states in the band structure (as opposed to the Sr films), hindering the electron transport.}