Observation of strontium segregation in LaAlO${}_3$/SrTiO${}_3$ and NdGaO${}_3$/SrTiO${}_3$ oxide heterostructures by X-ray photoemission spectroscopy

Abstract

LaAlO${}_3$ and NdGaO${}_3$ thin films of different thickness have been grown by pulsed laser deposition on TiO${}_2$-terminated SrTiO${}_3$ single crystals and investigated by soft X-ray photoemission spectroscopy. The surface sensitivity of the measurements has been tuned by varying photon energy $h\nu$ and emission angle $\Theta$. In contrast to the core levels of the other elements, the Sr $3d$ line shows an unexpected splitting for higher surface sensitivity, signaling the presence of a second strontium component. From our quantitative analysis we conclude that during the growth process Sr atoms diffuse away from the substrate and segregate at the surface of the heterostructure, possibly forming strontium oxide.

References in corpus (4)

• Magnetic effects at the interface between nonmagnetic oxides
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• Origin of Metallic States at Heterointerface between Band Insulators LaAlO${}_3$ and SrTiO${}_3$
• Persistent photoconductivity in 2-dimensional electron gases at different oxide interfaces

Cited by in corpus (1)

• Creating Two-Dimensional Electron Gas in Nonpolar Oxide Interface via Polarization Discontinuity: First-Principles Analysis of CaZrO3/SrTiO3 Heterostructure