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キーワード:
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要旨:
We combine (scanning) transmission electron microscopy, electron energy loss spectroscopy (EELS), and x-ray photoelectron spectroscopy (XPS) with density functional theory (DFT) to investigate the complex interplay of surface energetics and polar discontinuity compensation in the interface formation of (001) LaInO3/BaSnO3-based heterostructures. We present evidence from both experiment and theory that the BaSnO3 surface with BaO termination is energetically favored over a wide range of chemical potentials. However, overgrowth of the nonpolar BaO-terminated surface with LaInO3 results in a SnO2-terminated interface. EELS and XPS show that this interfacial termination exchange is mediated by Ba segregation to the growth surface. Our DFT calculations show that the efficient compensation of the polar discontinuity, attributed to polar distortions within BaSnO3 at the SnO2-terminated interface, serves as the driving force behind the observed Ba segregation. This intricate interplay underscores the importance of polar discontinuity compensation as a pivotal factor influencing interface formation in perovskite systems.
