Regensburg 2022 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 14: Focus session: Quantum Properties at Functional Oxide Interfaces 2 (joint session DS/HL)

DS 14.2: Vortrag

Mittwoch, 7. September 2022, 10:00–10:15, H17

A detailed interface and surface analysis of BaSnO₃ in LaInO₃/BaSnO₃ heterostructures — •Martina Zupancic¹, Wahib Aggoune², Daniel Pfützenreuter¹, Zbigniew Galazka¹, Houari Amari¹, Claudia Draxl², Jutta Schwarzkopf¹, and Martin Albrecht¹ — ¹Leibniz-Institut für Kristallzüchtung, Berlin, Germany — ²Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, Berlin, Germany

LaInO₃/BaSnO₃ heterostructures have lately attracted a lot of interest due to the high electron mobility of ∼300cm²/Vs in BaSnO₃ and the formation of a 2DEG at the interface. In LaAlO₃/SrTiO₃ system, the origin of the 2DEG is attributed to the polar discontinuity and an electronic reconstruction at the n-type LaO-TiO₂ interface. Controlling the interface termination is therefore crucial to accomplish heterostructures with desired properties. Here, we combine density-functional theory, atomic resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, and electron energy loss spectroscopy (EELS) to study the LaInO₃/BaSnO₃ interface. Experiment and theory are in excellent agreement and show that free BaSnO₃ (100) surfaces are BaO terminated, while the interface between BaSnO₃ and LaInO₃ is SnO₂ terminated. This finding indicates that during the growth of LaInO₃ layer on BaSnO₃ Ba atoms exchange from the subsurface to the surface. Preliminary EELS analysis of a few monolayer thick LaInO₃ grown on BaSnO₃ shows indications of Ba atoms on the LaInO₃ surface, confirming that atomic exchange in this system promotes the energetically favorable SnO₂-LaO interface.