XPS on oxide heterointerfaces
In 2004 Ohtomo and Hwang discovered that conductivity arises at the interface between TiO2 terminated SrTiO3 (STO) and LaAlO3 (LAO), two non conducting oxides. Later it was found that these interfaces not only conduct but can show signs of superconductivity and magnetism as well. The conductivity is suspected to be localised in a thin layer around the interface in a two dimensional electron gas (2DEG). The origin of this 2DEG is still under debate. Using X-ray photoelectron spectroscopy at our own setup, FAMoS, and at the HiKE endstation in Bessy, Berlin we can probe the 2DEG, measure band shifts and study the depth profile of these systems.
Below the Ti2p corelevel spectrum is shown for samples of varying LAO overlayer thickness. Also the spectrum of the valence band for the same samples is shown. The samples are grown by pulsed laser deposition at the University of Twente.
 1.) Ti2p corelevel spectrum for varying LAO overlayer thickness. |
 2.) Valence band spectra |
This project is the main focus of the PhD research carried out by Erik Slooten and is funded by FOM (08IP06). For more information, please contact Erik Slooten or Mark Golden