Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 56: Poster Session: Low-Dimensional Systems

TT 56.12: Poster

Mittwoch, 22. März 2017, 15:00–19:00, P2-OG4

Emergence of interfacial conductivity in the LaAlO₃ capped LaVO₃/SrTiO₃ heterostructure — •Martin Stübinger, Judith Gabel, Philipp Gagel, Michael Sing, and Ralph Claessen — Universität Würzburg, Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), 97074 Würzburg, Germany

Akin to the well known oxide heterostructure LaAlO₃/SrTiO₃ (LAO/STO) a conducting interface is found also between the strongly correlated, polar Mott insulator LaV³⁺O₃ (LVO) and the non-polar band insulator STO. Since LaV³⁺O₃ tends to overoxidize to the thermodynamically more stable LaV⁵⁺O₄ phase when exposed to air, a suitable passivation is required. Therefore, we have employed pulsed laser deposition thin film growth of LVO films with a crystalline LAO capping layer. In situ photoemission measurements of samples before and after being exposed to air show that the V oxidation state can indeed be stabilized by the LAO capping layer. By transport measurements, we identify an insulator-to-metal transition at a combined LAO/LVO overlayer thickness of 4 unit cells. The metallicity holds for different combinations of LAO and LVO thickness as long as the total overlayer thickness is 4 uc or higher. Thus, both LAO and LVO play a cooperative role in inducing interfacial conductivity in this system. We discuss these findings in terms of an interplay of the polar nature of LAO and LVO and defect states that provide mobile charge carriers.