Publication Type:Journal Article
Source:Journal of Applied Physics, Volume 110, Number 4 (2011)
Keywords:Electron energy loss spectroscopy, Electronic properties, Electronic structure, electrons, Energy-loss near-edge structure, Interface layer, Lanthanum alloys, Local bonding, Multi-electron, Perovskite, scanning transmission electron microscopy, Substrate surface, Theoretical calculations, thin films, transmission electron microscopy, Vanadium, Vanadium alloys, Z-contrast imaging
The atomic and electronic structures at interfaces in thin films are typically different from the bulk and are vitally important in determining the physical properties of thin films. The interface between SrVO3, chosen as a prototype for vanadium-based perovskite materials in this work, and LaAlO3 substrate is investigated by scanning transmission electron microscopy, electron energy-loss spectroscopy, and theoretical multi-electron calculations. Extra electrons have been detected on the interface layer by comparing the energy-loss near-edge structures of V-L3,2 edges to those from the film far from the interface. Monochromated EELS and theoretical calculations for SrVO3, VO2, and V2O 3 support this conclusion. The extra electrons appear to originate from a change in the local bonding configuration of V at the La-O terminated substrate surface as determined by Z-contrast imaging. © 2011 American Institute of Physics.
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