Probing the Electronic Structures of BaTiO3/SrTiO3 Multilayered Film with Spatially Resolved Electron Energy-Loss Spectroscopy

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• 作者：Guiju Liu ; Yiqian Wang ; Bin Zou ; Wenshuang Liang ; Neil M. Alford ; David W. McComb ; Peter K. Petrov
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：August 4, 2016
• 年：2016
• 卷：120
• 期：30
• 页码：16681-16686
• 全文大小：378K
• 年卷期：0
• ISSN：1932-7455

文摘

A multilayered film of BaTiO₃/SrTiO₃ was grown on a LaAlO₃ substrate using dual-target pulsed laser deposition technique. High-resolution scanning transmission electron microscopy observations show that the nine unit-cell BaTiO₃ layer and the three unit-cell SrTiO₃ layer are alternatively arranged in the epitaxial film where a sharp interface exists between the BaTiO₃ and SrTiO₃ layers. Electron energy-loss spectroscopy analysis demonstrates that the O-K edge spectra of SrTiO₃ and BaTiO₃ layers are quite distinct; in particular, the energy-loss peak at 547 eV in the SrTiO₃ spectrum splits into two peaks in the BaTiO₃ spectrum. The multiple-scattering calculations of O-K edge spectra for BaTiO₃ and SrTiO₃ agree well with the experimental results. The low-energy region (<542 eV) of the O-K edge spectra for both BaTiO₃ and SrTiO₃ is mainly caused by the hybridization of the O 2p with Ti 3d orbitals. The splitting peaks between 542 and 552 eV in the O-K edge spectra of BaTiO₃ are attributed to its complex crystal structure including two unequal oxygen sites and low site symmetry.