Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 94: Low-Dimensional Systems: Oxide Hetero-Interfaces
TT 94.2: Vortrag
Donnerstag, 3. April 2014, 15:15–15:30, HSZ 204
Direct k-space mapping of interface states in oxide-oxide heterostructures — •Florian Pfaff1, Hidenori Fujiwara2, Judith Gabel1, Götz Berner1, Atsushi Yamasaki3, Akira Sekiyama2, Yunzhong Chen4, Nini Pryds4, Shigemasa Suga5, 6, Michael Sing1, and Ralph Claessen1 — 1Physikalisches Institut and Röntgen Center for Complex Materials Systems (RCCM), Universität Würzburg — 2Graduate School of Engineering Science, Osaka University — 3Department of Physics, Konan University — 4Department of Energy Conversion and Storage, Technical University of Denmark, — 5Institute of Scientific & Industrial Research, Osaka University — 6Max-Planck-Institute for Microstructure Physics, Halle
The most prominent example of unexpected quantum phases that can form at oxide heterointerfaces is the 2D electron system (2DES) in LaAlO3/SrTiO3 (LAO/STO). Its origin has been related to electronic reconstruction due to the polar character of the LAO. The novel γ-Al2O3 (GAO)/STO also exhibits a 2DES with even higher mobility although GAO is regarded to be non-polar. Here, it is assumed that O vacancies at the STO side of the interface induce the 2DES. We have mapped the momentum-resolved electronic structure of the interface Ti 3d states by resonant soft x-ray photoemission for both types of heterostructures. While one can observe in both systems a dichotomy of mobile and trapped interface charges they also show remarkable differences regarding the proportion of mobile and trapped carriers as well as the electron dispersions and Fermi surfaces.