Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 40: Poster Session Correlated Electrons
TT 40.52: Poster
Mittwoch, 13. März 2013, 15:00–19:00, Poster D
Wetting an oxide heterostructure: influence of surface water adsorbates on the electronic properties of LaAlO3/SrTiO3 studied by in situ photoelectron spectroscopy — •Philipp Scheiderer1, Florian Pfaff1, Judith Gabel1, Mihaela Gorgoi2, Michael Sing1, and Ralph Claessen1 — 1Universität Würzburg, Physikalisches Institut — 2BESSY II., Albert-Einstein-Strasse 15, Berlin
Oxide heterostructures display many interesting phenomena, one example being the formation of a two-dimensional electron system (2DES) at the LaAlO3/SrTiO3 (LAO/STO) interface beyond a critical thickness of 4 monolayers (ML) of the polar LAO [1,2]. An explanation for this behavior is the so-called electronic reconstruction. In this context it was recently shown that polar adsorbates can enhance the conductivity of the 2DES [3]. Besides their electrostatic influence it was discussed that surface defects/adsorbates can also act as a charge reservoir [4]. To examine the impact of surface adsorbates on the 2DES we performed in situ photoelectron spectroscopy on 6ML thick LAO/STO heterostructures exposed to a defined amount of water vapor. In response to the adsorbed water we observe an increase of charge carriers at titanium sites. Furthermore a comparison between bulk and interface sensitive measurements indicates that the additional charge carriers are located at the interface.
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Bristowe et al., Phys. Rev. B 83, 205405 (2011)