Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 8: Low-Dimensional Systems: Oxide Hetero-Interfaces

TT 8.4: Vortrag

Montag, 16. März 2015, 10:15–10:30, H 3010

Oxygen Dosing the Surface of SrTiO₃ — •L. Dudy¹, P. Scheiderer¹, J.D. Denlinger², P. Schütz¹, J. Gabel¹, M. Buchwald¹, C. Schlueter³, T.-L. Lee³, M. Sing¹, and R. Claessen¹ — ¹Physikalisches Institut, Universität Würzburg, D-97074 Würzburg, Germany — ²Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94270, USA — ³Diamond Light Source Ltd., Didcot, Oxfordshire OX11 0DE, United Kingdom

The highly mobile two-dimensional electron system (2DES) on the surface of the insulating SrTiO₃(STO) offers exciting perspectives for advanced material design. This 2DES resides in a depletion layer caused by oxygen deficiency of the surface. With photoemission spectroscopy, we monitor the appearance of quasi-particle weight (QP) at the Fermi energy and oxygen vacancy induced states in the band gap (IG). Both, QP and IG weight, increase and decrease respectively upon exposure to extreme ultraviolet (XUV) light and in-situ oxygen dosing. By a proper adjustment of oxygen dosing, any intermediate state can be stabilized providing full control over the charge carrier density. From a comparison of the charge carrier concentrations obtained from an analysis of core-level spectra and the Fermi-surface volume, we conclude on a spatially inhomogeneous surface electronic structure with at least two different phases.