Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 59: Low-Dimensional Systems: Poster Session

TT 59.14: Poster

Mittwoch, 9. März 2016, 15:00–18:30, Poster D

Stabilization of stoichiometric LaTiO₃ thin films grown by pulsed laser deposition — •Matthias Schmitt, Philipp Scheiderer, Alex Gößmann, Michael Sing, and Ralph Claessen — Universität Würzburg, Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), 97074 Würzburg, Germany

Like in the famous oxide heterostructure LaAlO₃/SrTiO₃ (LAO/STO) a two dimensional electron system is found at the interface between the strongly correlated Mott insulator LaTi³⁺O₃ and the band insulator STO. In contrast to LAO, the stabilization of LaTi³⁺O₃ requires strong reducing growth conditions since the thermodynamically stable bulk phase is the oxygen-rich La₂Ti₂⁴⁺O₇. Therefore, we have systematically studied the impact of oxidizing and reducing background atmospheres and the influence of the substrate on LaTi³⁺O₃ thin film growth by pulsed laser deposition. In situ x-ray photoelectron spectroscopy of the films prepared on STO exhibit overoxidation probably due to oxygen out-diffusion from the STO substrate, which is reduced for growth on DyScO₃ due to the lower oxygen mobility. In addition, we found that a LAO capping layer of a few unit cells thickness acting like a diffusion barrier for oxygen prevents the LTO film from overoxidation during storage in air.