Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 13: Poster: Interfaces and Thin Films
CPP 13.36: Poster
Dienstag, 27. März 2012, 18:15–20:45, Poster A
Site specific electronic structure of electron doped SrTiO3 and SrTiO3 /LaAlO3 interfaces — •Christoph Schlueter1, Tien-Lin Lee2, Carmela Aruta3, and Jörg Zegenehagen1 — 1ESRF,Grenoble, France — 2Diamond Light Source Ltd, Didcot, UK — 3CNR-SPIN, Naples, Italy
A quasi-2dimensional electron gas is formed at the interface of the insulation oxides SrTiO3 (STO) and LaAlO3 (LAO). Despite significant research efforts the origin of the conductivity is still heavily discussed. This electron gas is expected to occupy states up to the Fermi level.
We present results of hard X-ray photoelectron spectroscopy (HAXPES) measurements on the STO/LAO hetero structures in comparison to electron doped single crystalline STO samples. Additional information is added by combining HAXPES with the site specific X-ray standing wave effect. This gives the possibility to decompose the spectra into the relative contributions from different lattice sites. Hence, coherent and incoherent (delocalized/localized) states close to the Fermi level can be distinguished. The obtained spectra show a partial filling of Ti d-bands, crossing the Fermi level. Oxygen deficient samples exhibit an additional incoherent peak +1.3eV below the Fermi level. For the hetero structures we identified carriers at the Fermi level from the conductive interface region and give experimental evidence of partial filling of Ti 3d bands and the presence of the oxygen vacancy related incoherent peak.