Interface dipole between two metallic oxides caused by localized oxygen vacancies

Albina Y. Borisevich,
Andrew R. Lupini,
Jun He,
Anna N. Morozovska,
George S. Svechnikov,
Pu Yu,
Ying-Hao Chu,
Ramamoorthy Ramesh,
Sokrates T. Pantelides,
Sergei V. Kalinin,
Stephen J. Pennycook

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krzhizhanovsky str., 3, Kyiv, 03142, Ukraine
Physical Review B - Maryland, USA: American Physical Society (APS), 2012, #86


Oxygen vacancies are increasingly recognized to play a role in phenomena observed at transition-metal oxide interfaces. Here, we report a study of SrRuO3 and La0.7Sr0.3MnO3 interfaces using a combination of quantitative aberration-corrected scanning transmission electron microscopy, electron energy-loss spectroscopy, and density functional calculations. Cation displacements are observed at the interface, indicative of a dipolelike electric field even though both materials are nominally metallic. The observed displacements are reproduced by theory if O vacancies are present in the near-interface La0.7Sr0.3MnO3 layers. The results suggest that atomic-scale structural mapping can serve as a quantitative indicator of the presence of O vacancies at interfaces.