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Local Dielectric Breakdown Path along c ‐Axis Planar Boundaries in Cr 2 O 3 Thin Films
Author(s) -
Sun Congli,
Song Zhewen,
Rath Ashutosh,
Street Michael,
Echtenkamp William,
Feng Jie,
Binek Christian,
Morgan Dane,
Voyles Paul
Publication year - 2017
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201700172
Subject(s) - materials science , condensed matter physics , thin film , scanning transmission electron microscopy , planar , electron energy loss spectroscopy , scattering , band gap , dielectric , transmission electron microscopy , molecular physics , optics , optoelectronics , physics , nanotechnology , computer graphics (images) , computer science
The 3D atomic structure of an interface‐stabilized planar boundary in the magnetoelectric Cr 2 O 3 thin films is reported based on scanning transmission electron microscopy as a function of scattering angle. Local boundary electron energy loss spectroscopy shows a prepeak on the O–K edge arising from unoccupied O 2p states. Density functional theory calculations reproduce the images and spectra and show that the boundary has smaller bandgap than bulk Cr 2 O 3 , but does not interrupt the (0001) surface spin polarization and boundary magnetization. The reduced bandgap at the boundaries means they provide potential breakdown paths in Cr 2 O 3 thin films. The same planar defect is predicted to occur in other epitaxial corundum film/substrate systems.